资源简介

INCLUDEPICTURE "第十八章S.tif" INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT
INCLUDEPICTURE "课标要求S.tif" INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT
1．通过实验，认识磁场．知道地磁场．
2．通过实验，了解电流周围存在磁场．探究并了解通电螺线管外部磁场的方向．了解电磁铁在生产生活中的应用．
3．通过实验，了解通电导线在磁场中会受到力的作用，并知道力的方向与哪些因素有关．
4．探究并了解导体在磁场中运动时产生感应电流的条件．了解电磁感应在生产生活中的应用．
INCLUDEPICTURE "思维导图S.tif" INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT
INCLUDEPICTURE "26JXWL-16.tif" INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT
INCLUDEPICTURE "考点清单命题探源S.tif" INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT
考点一　磁现象
磁性 物体能够吸引 等物质的性质
磁体 定义 具有磁性的物体
性质 磁体具有 ，磁体周围存在着
磁极 定义 磁体的吸引能力最 的两个部位
名称 任何磁体都有两个磁极，分别叫作 极( 极)和 极( 极)
作用 同名磁极相互 ，异名磁极相互
磁化 定义 有些物体在 或 的作用下会获得磁性，这种现象叫作磁化
考点二　磁场
磁场 存在 周围存在着磁场
性质 磁场对放入其中的磁体有 的作用
作用 磁体间的相互作用都是通过 来发生的
方向 在磁场中的某一点，小磁针静止时 极所指的方向就是该点的磁场方向
磁感线 定义 我们把小磁针在磁场中的排列情况，用一些带箭头的曲线画出来，可以方便、形象地描述磁场，这样的曲线叫作磁感线
方向 磁感线是一些闭合的曲线，在磁体的外部，磁感线从磁体的 极出发，最后回到 极；在磁体内部，磁感线从 极出发回到 极
特点 (1)磁感线上任何一点的 方向，就是该点的磁场方向；(2)磁感线分布越密的地方，其磁场越 ；磁感线分布越疏的地方，其磁场越
分布 INCLUDEPICTURE "25W-1806.tif" INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT 条形磁体的磁场分布 蹄形磁体的磁场分布 INCLUDEPICTURE "25W-1808.tif" INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT 同名磁极间的磁场分布 INCLUDEPICTURE "25W-1809.tif" INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT 异名磁极间的磁场分布
地磁场 定义 地球周围存在磁场
地磁分布 如图所示，地磁N极在地理 附近，地磁S极在地理 附近 INCLUDEPICTURE "25W-1810.tif" INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT
磁偏角 地理的两极和地磁场的两极并不重合，最早由我国宋代学者 记述
考点三　电流的磁效应
1．电流的磁效应
奥斯特实验 现象 INCLUDEPICTURE "25W-1811.tif" INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT 　 INCLUDEPICTURE "25W-1812.tif" INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT 　 INCLUDEPICTURE "25W-1813.tif" INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT 　甲 通电　　乙 断电　丙 改变电流方向
结论 通电导体周围存在着 ，通电导体周围磁场的方向与 有关
通电螺线管的磁场 特点 通电螺线管周围的磁场与条形磁体的磁场相似
磁极判断 安培定则：用 手握住螺线管，让四指指向螺线管中 ，则拇指所指的那端就是螺线管的 极 INCLUDEPICTURE "25W-1814.tif" INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT
2.电磁铁
结构 内部插入 的通电螺线管
原理 电流的 效应
探究影响电磁铁磁性强弱的因素 探究方法 (1) 法；(2) 法(电磁铁磁性的强弱可通过吸引铁钉的多少来判断)
结论 匝数一定时，通过电磁铁的 越大，磁性越强；电流一定时，电磁铁 越多，磁性越强
优点 电磁铁磁性的有无可以通过 来控制
电磁铁磁性的强弱可以通过线圈中 和 来控制
电磁铁磁极的方向可以由电流方向和线圈绕向来控制
3.电磁继电器
电磁继电器 实质 利用电磁铁来控制工作电路的一种开关
工作原理图 INCLUDEPICTURE "25W-1815.tif" INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT
作用 利用 、弱电流电路的通断，来间接地控制 、强电流电路的通断
考点四　磁场对通电导体的作用
图示 INCLUDEPICTURE "25W-1816.tif" INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT
内容 磁场对通电导体具有 的作用
导体受力方向 通电导体在磁场中受力方向与 方向和 方向有关
导体运动快慢 通电导体在磁场中运动的快慢与 大小和 的强弱有关
应用 电动机、扬声器等
考点五　电动机的工作原理
直流电动机 原理 电动机是根据 的原理制成的
示意图 INCLUDEPICTURE "25W-1817.tif" INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT
构造 直流电动机主要由 、磁极、 、电刷等组成
换向器：每当线圈刚转过平衡位置时，换向器就自动改变线圈中的 ，使线圈连续转动下去
能量转化 能转化为 能
考点六　电能的来源
电池 定义 电池是一种把其他形式的能转化为 能的装置，电池提供的是 电
类型 化学电池 蓄电池充电时，将 能转化为 能；使用时，将 能转化为 能
太阳能电池 将 能转化成 能
发电机 火力发电 燃料的 能→水和水蒸气的 能→发电机转子的机械能→电能
水力发电 水的 能→水轮机的 能→发电机转子的 能→电能
核能发电 能→水和蒸汽的 能→发电机转子的 能→电能
考点七　电磁感应原理
发现 英国科学家 于1831年发现了电磁感应现象
图示 INCLUDEPICTURE "25W-1819.tif" INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT
内容 闭合电路的一部分导体在磁场中做 运动时，导体中就产生电流．这种由于导体在磁场中运动而产生电流的现象叫作电磁感应，产生的电流叫作
感应电流产生的条件 ① ；②
感应电流方向 与 和 有关
应用 发电机、动圈式话筒等
考点八　发电机原理
发电机 原理 根据 原理制造
图示 INCLUDEPICTURE "25W-1820.tif" INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT
工作原理 发电机工作时，线圈 磁感线，线圈中产生 ；线圈每半周改变一次转动方向，线圈中的电流方向就随着改变一次
能量转化 能转化为 能
INCLUDEPICTURE "深化辨析FS.tif" INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT
判断正误(正确的画“√”，错误的画“×”)
1．磁场中某点的磁场方向是由放在该点的小磁针决定的．(　　)
2．小磁针自由静止时，小磁针的N极指向地磁场的S极．(　　)
3．磁感线是实际存在的线，在磁场中反映了各点的磁场方向．(　　)
4．最早记录地理的两极和地磁场的两极不重合这一现象的是我国宋代学者沈括．(　　)
5．磁场对放入其中的小磁针一定有力的作用．(　　)
6．磁体之间的相互作用是通过磁场发生的．(　　)
7．利用撒在磁体周围的铁屑可以判断该磁体周围各点的磁场方向．(　　)
INCLUDEPICTURE "重难突破方法探寻S.tif" INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT
安培定则的应用
?方法指导
(1)确定通电螺线管、小磁针的N、S极．
INCLUDEPICTURE "25W-1827.tif" INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT
(2)确定通电螺线管中电流的方向、电源正负极．
INCLUDEPICTURE "25W-1828.tif" INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT
(3)确定通电螺线管上的绕线方向．
INCLUDEPICTURE "25W-1829.tif" INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT
?典例集训
INCLUDEPICTURE "25W-1830.tif" INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT
1．如图所示，由通电螺线管的磁感线方向可知，电流表的上端为________接线柱；静止的小磁针的左端为________极．
2．如图所示，请根据通电螺线管附近静止小磁针的指向，用箭头在A点标出磁感线方向，在B点标出电流方向．
INCLUDEPICTURE "25W-1831.tif" INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT
3．如图所示，请根据小磁针指向确定电源a端的极性，将“＋”或“－”填在(　　)内．
INCLUDEPICTURE "25W-1833.tif" INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT
三种电磁现象辨识
?方法指导
四种电磁实验
实验 奥斯特实验 电磁感应实验 探究磁场对通电导线的作用实验 探究电磁铁磁性强弱的影响因素
装置图 INCLUDEPICTURE "25W-1834.tif" INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT
工作原理 电流的磁效应 电磁感应 通电导体在磁场中受力运动 电流的磁效应
能量转化 — 机械能→电能 电能→机械能 —
影响因素 磁场的方向与电流方向有关 感应电流的方向与磁场的方向、导体切割磁感线的运动方向有关 导体受力的方向与电流的方向、磁场方向有关 电磁铁磁性强弱与电流大小、线圈匝数有关
判断依据 — 电路中无电源 电路中有电源 —
主要应用 电磁铁、电磁继电器 发电机、动圈式话筒 电动机、扬声器 电磁继电器、电磁起重机
?典例集训
4．下列有关电与磁的描述，正确的是(　　)
INCLUDEPICTURE "25W-1838.tif" INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT
甲 乙 丙 丁
A．图甲：根据安培定则，大拇指所指的那端为通电螺线管的S极
B．图乙：电磁继电器就是用永磁体控制工作电路的一种开关
C．图丙：通电线圈在磁场中受力转动，是电动机的工作原理
D．图丁：导线AB左右往复运动过程中，产生的感应电流方向不变
5．(多选)如图所示，是各实验现象所揭示的原理或规律与其所对应的应用技术，其中正确的是(　　)
INCLUDEPICTURE "25W-1842.tif" INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT
A　　　　　　　 　　　B
INCLUDEPICTURE "25W-1843.tif" INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT
C　　　　　　　　　　D
INCLUDEPICTURE "实验探究能力提升S.tif" INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT
实验一　探究通电螺线管外部磁场的方向
?探究要点
实验器材的选取及作用 (1)小磁针的作用：显示磁场的方向；(2)在通电螺线管周围不同位置放置小磁针的目的：便于观察不同点的磁场方向；(3)螺线管中插入铁棒的目的：增加螺线管的磁场强度
实验关键操作 (1)在嵌入螺线管的玻璃板上均匀撒些细铁屑，通电后轻敲玻璃板的目的：减小铁屑与玻璃板的摩擦，使铁屑只受磁场作用而排列；(2)电源正负极对调的目的：探究通电螺线管的磁场方向与电流方向是否有关
转换法的应用 (1)根据小磁针的指向判断通电螺线管的极性；(2)通过铁屑的密集程度判断磁场的强弱
实验结论 (1)通电螺线管外部的磁场与条形磁体的磁场相似；(2)磁场方向和电流方向有关
?典例集训
1．实验小组的同学们在“探究通电螺线管外部磁场的特点”实验．
INCLUDEPICTURE "25W-1844.tif" INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT
甲 乙 丙
(1)小明先根据图甲连接好实验装置，在小圆圈位置放置________，目的是____________________；实验时________(选填“能”或“不能”)用大头针代替小磁针．
(2)闭合开关，小磁针的指向如图乙所示，则通电螺线管的左端为________极；小磁针涂黑的一端为________极．(均选填“N”或“S”)
(3)通过观察图乙，可以初步得出结论：通电螺线管外部的磁场与________的磁场相似；为描述磁场而引入的磁感线________(选填“是”或“不是”)真实存在的．
(4)为了研究通电螺线管的磁极性质，小明与小聪一起对螺线管可能的电流方向和绕线方式进行了实验，得到了下列四种情况．实验说明通电螺线管的磁极极性只与它的________有关．
INCLUDEPICTURE "25W-1847.tif" INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT
A B C D
(5)小聪在嵌入螺线管的玻璃板上均匀撒些细铁屑．通电后轻敲玻璃板，使铁屑与玻璃板微微分离，从而减小铁屑与玻璃板间的________．待细铁屑不再移动后，排列如图丙所示，观察实验现象，这样做的好处是
__________________________________________________________.(合理即可)
(6)小聪进行图丙实验时，若发现通电螺线管的磁场较弱，铁屑规则排列的效果不明显，想要增强通电螺线管周围的磁场强度，在不更换螺线管的前提下，可行的改进措施是________________________________________________________．
(写出一种方法即可)
实验二　探究导体在磁场中运动时产生感应电流的条件
?探究要点
1．实验原理(电磁感应现象).
2．实验装置
INCLUDEPICTURE "25W-1851.tif" INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT
3．转换法的应用：观察电流计的指针是否偏转来判断是否产生感应电流．
4．控制变量法的应用：
(1)探究感应电流方向与磁场方向的关系：控制导体运动方向不变，改变磁场方向．
(2)探究感应电流方向与导体运动方向的关系：控制磁场方向不变，改变导体运动方向．
5．产生感应电流的条件：①闭合电路；②闭合电路中的一部分导体切割磁感线．
6．影响感应电流方向的因素：①磁场方向；②导体运动方向．
7．影响感应电流大小的因素：①磁场强弱；②导体切割磁感线的速度．
8．感应电流产生过程中的能量转化：机械能转化为电能．
9．实验现象分析及处理方法：
(1)导体在磁场中运动时，电流计不偏转的原因：没有感应电流产生或产生的感应电流很小．
(2)要使电流计偏转明显可采取的措施：加快导体切割磁感线的速度、增加磁场强度、用多匝线圈或多根导线替代单根导线等．
10．电磁感应现象在生活中的应用：发电机、动圈式话筒．
11．实验结论：闭合电路的一部分导体在磁场中做切割磁感线运动产生感应电流，电流的方向与磁场方向和导体运动方向有关．
?典例集训
2．发电机是如何发电的呢？如图所示，同学们在蹄形磁体的磁场中放置一根导线ab，导线ab的两端跟电流表连接，导线跟电流表组成了闭合电路．
INCLUDEPICTURE "25W-1852.tif" INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT
(1)实验中可以通过电流表的指针是否________来判断电路中是否有感应电流产生；通过电流表指针的偏转方向来判断______________；通过指针的____________来判断感应电流的大小．
(2)当导线ab悬挂起来静止后，电流表指针不偏转，说明电路中________(选填“有”或“无”)感应电流产生．
(3)小芳无意间碰到导线ab，导线ab晃动起来，小明发现电流表指针发生了偏转，就说：“让导体在磁场中运动就可产生电流．”但小芳说：“不一定，还要看导体怎样运动．”为验证猜想，他们继续探究，并把观察到的现象记录如下：
序号 磁体摆放方向 导线ab运动方向 电流表指针偏转情况
1 N极在上 竖直上下运动 不偏转
2 水平向左运动 向右偏转
3 水平向右运动 向左偏转
4 N极在下 竖直上下运动 不偏转
5 水平向左运动 向左偏转
6 水平向右运动 向右偏转
分析实验现象与数据，可得出小芳的观点是________(选填“正确”或“错误”)的．
(4)比较第2、3次实验现象发现，产生的电流的方向跟____________________有关；比较第3、6次实验现象发现，产生的电流的方向还跟________有关．
(5)在整理器材时，小明撤去蹄形磁体，有同学发现指针又偏转了．他们再重复刚才的操作，发现电流表的指针会偏转．请教老师后得知，不论是导体运动还是磁体运动，只要闭合电路的一部分导体在________中做________________运动，电路中就会产生感应电流．这最早由英国物理学家________发现．
(6)电路产生感应电流的过程中将________能转化为电能，利用此原理可用来制造________(选填“电动机”或“发电机”).
(7)本实验中________(选填“可以”或“不可以”)用小灯泡代替电流表，原因是_________________________________________________________________________________________________________________________________________.
(8)想要探究磁场对通电导体的作用，只需将________更换为________．
INCLUDEPICTURE "真题在线明晰考向S.tif" INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT
1．(2021·T1)下图是我国古代四大发明之一的指南针——司南，静止时它的长柄指向地理的________方．在11世纪，我国宋代学者________就发现了地理两极和地磁两极并不重合，这个发现比西方早了400多年．
INCLUDEPICTURE "26JXWL-103.tif" INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT
2．(2024·T4)在大力倡导节能环保、践行低碳生活的新时代，新能源汽车越来越普及．其中新能源电动汽车中的电动机利用通电线圈在________中受力转动，把________能转化为机械能，从而驱动汽车行驶．
3．(2022·T4)如图所示，这是某同学在科技节上展示的作品结构图．该作品的工作原理是通电线圈在________中受力转动，它就是一个自制的________机模型图．
INCLUDEPICTURE "26JXWL-104.tif" INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT
4．(2023·T4)如图所示，卸下家用微型风扇的插头后，将两根导线分别与灵敏电流计连接起来，用力转动风扇叶子，看到灵敏电流计的指针偏转，这是________________现象，此过程中机械能转化为________能．
INCLUDEPICTURE "26JXWL-105.tif" INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT
5．(2021·T11)下图是燃油汽车启动装置的电路简图．汽车启动时，需将钥匙插入仪表板上的钥匙孔并旋转，则下列分析正确的是(　　)
INCLUDEPICTURE "26JXWL-106.tif" INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT
A．旋转钥匙相当于闭合开关
B．电磁铁是利用电流的热效应来工作的
C．电磁铁通电后电磁铁的上端为S极
D．电动机工作时将电能全部转化为机械能
6．(2019·T15)如图所示，这是小安同学自制的一个实验装置，他把带绝缘层的导线绕在塑料管外，导线两端连接着小灯泡，形成闭合电路，管内封闭一个强磁体，沿图中所示方向来回快速摇动装置，小灯泡发光．以下说法正确的是(　　)
INCLUDEPICTURE "26JXWL-107.tif" INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT
A．灯丝中电流方向保持不变
B．实验现象表明电能够生磁
C．该现象属于电磁感应现象
D．此装置与电动机原理相同
7．(2022·T12)如图所示，这是某同学自制的简易电磁锁原理图．闭合开关S，滑片P向左移动，使静止在水平桌面的条形磁体滑动，打开门锁．下列说法正确的是(　　)
INCLUDEPICTURE "26JXWL-108.tif" INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT
A．通电后电磁铁a端为S极
B．滑片向左移动的过程中电磁铁的磁性增强
C．条形磁体在滑动过程中受到向左的摩擦力
D．条形磁体在滑动过程中受到的摩擦力变小
8．(2024·T12)如图所示，通电螺线管旁的小磁针分别静止在图示位置．请科学推断，最终决定通电螺线管极性的是(　　)
INCLUDEPICTURE "26JXWL-109.tif" INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT
甲 乙 丙 丁
A．电源正负极的接法
B．螺线管导线的环绕方向
C．小磁针静止时N极的指向
D．螺线管中电流的方向
9．(2020·T25，节选)探究磁与电的联系．如图甲所示，是灵敏电流计的内部结构．小红同学参加课外实践活动，发现灵敏电流计内部结构与电动机、发电机内部结构类似．出于好奇，她利用如图乙所示的装置进行了下面的实验．
【进行实验】用手拨动其中一个灵敏电流计指针的同时，另一个灵敏电流计的指针也发生了偏转．
【交流】拨动右侧灵敏电流计的指针时，表内线圈在磁场中________________运动，产生了感应电流．于是，左侧灵敏电流计内的线圈同时也会有电流，它在________中受到力的作用，带动指针偏转起来．此时的右侧灵敏电流计相当于________机．
INCLUDEPICTURE "26JXWL-110.tif" INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT
甲 乙
10．(2025·T20)探究通电螺线管外部磁场的方向
某组同学通过探究，已了解通电螺线管的两端相当于条形磁体的两极，它们的极性可以用小磁针的指向来判定后，接着探究通电螺线管两端的极性由什么因素决定．
【猜想】
A．可能由螺线管的绕向决定
B．可能由电源正负极的接法决定
C．可能由螺线管中电流的方向决定
(注解：螺线管两接线柱和电源正负极的接法简称电源正负极的接法)
INCLUDEPICTURE "26JXWL-327.tif" INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT
【证据】用________将如图所示的器材连接成电路，把小磁针放在螺线管两端，闭合开关，观察并记录小磁针静止时N极的指向、螺线管的绕向、电源正负极的接法、螺线管中电流的方向．如图所示，是本组同学用画图的方法呈现出的四次实验现象．
INCLUDEPICTURE "26JXWL-328.tif" INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT
甲 乙
INCLUDEPICTURE "26JXWL-328B．tif" INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT
丙 丁
【解释】
(1)观察分析图甲、乙两图，螺线管的绕向相同，通电螺线管的同一端磁极________；
(2)观察分析图甲、丙两图，电源正负极的接法相同，通电螺线管的同一端磁极________；
(3)观察分析图________两图，螺线管中电流的方向相同，通电螺线管的同一端磁极相同；
(4)分析以上证据可知，通电螺线管的极性由螺线管中________决定，而不决定于________，也不决定于________________．INCLUDEPICTURE "第十八章S.tif" INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT INCLUDEPICTURE "第十八章S.tif" \* MERGEFORMAT
INCLUDEPICTURE "课标要求S.tif" INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT INCLUDEPICTURE "课标要求S.tif" \* MERGEFORMAT
1．通过实验，认识磁场．知道地磁场．
2．通过实验，了解电流周围存在磁场．探究并了解通电螺线管外部磁场的方向．了解电磁铁在生产生活中的应用．
3．通过实验，了解通电导线在磁场中会受到力的作用，并知道力的方向与哪些因素有关．
4．探究并了解导体在磁场中运动时产生感应电流的条件．了解电磁感应在生产生活中的应用．
INCLUDEPICTURE "思维导图S.tif" INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT INCLUDEPICTURE "思维导图S.tif" \* MERGEFORMAT
INCLUDEPICTURE "26JXWL-16.tif" INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-16.tif" \* MERGEFORMAT
INCLUDEPICTURE "考点清单命题探源S.tif" INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT INCLUDEPICTURE "考点清单命题探源S.tif" \* MERGEFORMAT
考点一　磁现象
磁性 物体能够吸引铁、钴、镍等物质的性质
磁体 定义 具有磁性的物体
性质 磁体具有磁性，磁体周围存在着磁场
磁极 定义 磁体的吸引能力最强的两个部位
名称 任何磁体都有两个磁极，分别叫作北极(N极)和南极(S极)
作用 同名磁极相互排斥，异名磁极相互吸引
磁化 定义 有些物体在磁体或电流的作用下会获得磁性，这种现象叫作磁化
考点二　磁场
磁场 存在 磁体周围存在着磁场
性质 磁场对放入其中的磁体有力的作用
作用 磁体间的相互作用都是通过磁场来发生的
方向 在磁场中的某一点，小磁针静止时N极所指的方向就是该点的磁场方向
磁感线 定义 我们把小磁针在磁场中的排列情况，用一些带箭头的曲线画出来，可以方便、形象地描述磁场，这样的曲线叫作磁感线
方向 磁感线是一些闭合的曲线，在磁体的外部，磁感线从磁体的N极出发，最后回到S极；在磁体内部，磁感线从S极出发回到N极
特点 (1)磁感线上任何一点的切线方向，就是该点的磁场方向；(2)磁感线分布越密的地方，其磁场越强；磁感线分布越疏的地方，其磁场越弱
分布 INCLUDEPICTURE "25W-1806.tif" INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1806.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1807.tif" \* MERGEFORMAT 条形磁体的磁场分布 蹄形磁体的磁场分布 INCLUDEPICTURE "25W-1808.tif" INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1808.tif" \* MERGEFORMAT 同名磁极间的磁场分布 INCLUDEPICTURE "25W-1809.tif" INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1809.tif" \* MERGEFORMAT 异名磁极间的磁场分布
地磁场 定义 地球周围存在磁场
地磁分布 如图所示，地磁N极在地理南极附近，地磁S极在地理北极附近 INCLUDEPICTURE "25W-1810.tif" INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1810.tif" \* MERGEFORMAT
磁偏角 地理的两极和地磁场的两极并不重合，最早由我国宋代学者沈括记述
考点三　电流的磁效应
1．电流的磁效应
奥斯特实验 现象 INCLUDEPICTURE "25W-1811.tif" INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1811.tif" \* MERGEFORMAT 　 INCLUDEPICTURE "25W-1812.tif" INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1812.tif" \* MERGEFORMAT 　 INCLUDEPICTURE "25W-1813.tif" INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1813.tif" \* MERGEFORMAT 　甲 通电　　乙 断电　丙 改变电流方向
结论 通电导体周围存在着磁场，通电导体周围磁场的方向与电流方向有关
通电螺线管的磁场 特点 通电螺线管周围的磁场与条形磁体的磁场相似
磁极判断 安培定则：用右手握住螺线管，让四指指向螺线管中电流的方向，则拇指所指的那端就是螺线管的N极 INCLUDEPICTURE "25W-1814.tif" INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1814.tif" \* MERGEFORMAT
2.电磁铁
结构 内部插入软铁棒的通电螺线管
原理 电流的磁效应
探究影响电磁铁磁性强弱的因素 探究方法 (1)控制变量法；(2)转化法(电磁铁磁性的强弱可通过吸引铁钉的多少来判断)
结论 匝数一定时，通过电磁铁的电流越大，磁性越强；电流一定时，电磁铁线圈匝数越多，磁性越强
优点 电磁铁磁性的有无可以通过电流的通断来控制
电磁铁磁性的强弱可以通过线圈中电流大小和线圈匝数来控制
电磁铁磁极的方向可以由电流方向和线圈绕向来控制
3.电磁继电器
电磁继电器 实质 利用电磁铁来控制工作电路的一种开关
工作原理图 INCLUDEPICTURE "25W-1815.tif" INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1815.tif" \* MERGEFORMAT
作用 利用低电压、弱电流电路的通断，来间接地控制高电压、强电流电路的通断
考点四　磁场对通电导体的作用
图示 INCLUDEPICTURE "25W-1816.tif" INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1816.tif" \* MERGEFORMAT
内容 磁场对通电导体具有力的作用
导体受力方向 通电导体在磁场中受力方向与电流方向和磁场方向有关
导体运动快慢 通电导体在磁场中运动的快慢与电流大小和磁场的强弱有关
应用 电动机、扬声器等
考点五　电动机的工作原理
直流电动机 原理 电动机是根据通电线圈在磁场中受力转动的原理制成的
示意图 INCLUDEPICTURE "25W-1817.tif" INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1817.tif" \* MERGEFORMAT
构造 直流电动机主要由线圈、磁极、换向器、电刷等组成
换向器：每当线圈刚转过平衡位置时，换向器就自动改变线圈中的电流方向，使线圈连续转动下去
能量转化 电能转化为机械能
考点六　电能的来源
电池 定义 电池是一种把其他形式的能转化为电能的装置，电池提供的是直流电
类型 化学电池 蓄电池充电时，将电能转化为化学能；使用时，将化学能转化为电能
太阳能电池 将太阳能转化成电能
发电机 火力发电 燃料的化学能→水和水蒸气的内能→发电机转子的机械能→电能
水力发电 水的机械能→水轮机的机械能→发电机转子的机械能→电能
核能发电 核能→水和蒸汽的内能→发电机转子的机械能→电能
考点七　电磁感应原理
发现 英国科学家法拉第于1831年发现了电磁感应现象
图示 INCLUDEPICTURE "25W-1819.tif" INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1819.tif" \* MERGEFORMAT
内容 闭合电路的一部分导体在磁场中做切割磁感线运动时，导体中就产生电流．这种由于导体在磁场中运动而产生电流的现象叫作电磁感应，产生的电流叫作感应电流
感应电流产生的条件 ①电路闭合；②部分导体做切割磁感线运动
感应电流方向 与磁场方向和导体运动方向有关
应用 发电机、动圈式话筒等
考点八　发电机原理
发电机 原理 根据电磁感应原理制造
图示 INCLUDEPICTURE "25W-1820.tif" INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1820.tif" \* MERGEFORMAT
工作原理 发电机工作时，线圈切割磁感线，线圈中产生电流；线圈每半周改变一次转动方向，线圈中的电流方向就随着改变一次
能量转化 机械能转化为电能
INCLUDEPICTURE "深化辨析FS.tif" INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT INCLUDEPICTURE "深化辨析FS.tif" \* MERGEFORMAT
判断正误(正确的画“√”，错误的画“×”)
1．磁场中某点的磁场方向是由放在该点的小磁针决定的．(　　)
2．小磁针自由静止时，小磁针的N极指向地磁场的S极．(　　)
3．磁感线是实际存在的线，在磁场中反映了各点的磁场方向．(　　)
4．最早记录地理的两极和地磁场的两极不重合这一现象的是我国宋代学者沈括．(　　)
5．磁场对放入其中的小磁针一定有力的作用．(　　)
6．磁体之间的相互作用是通过磁场发生的．(　　)
7．利用撒在磁体周围的铁屑可以判断该磁体周围各点的磁场方向．(　　)
答案：1.×　2.√　3.×　4.√　5.√　6.√　7．×
INCLUDEPICTURE "重难突破方法探寻S.tif" INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT INCLUDEPICTURE "重难突破方法探寻S.tif" \* MERGEFORMAT
安培定则的应用
?方法指导
(1)确定通电螺线管、小磁针的N、S极．
INCLUDEPICTURE "25W-1827.tif" INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1827.tif" \* MERGEFORMAT
(2)确定通电螺线管中电流的方向、电源正负极．
INCLUDEPICTURE "25W-1828.tif" INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1828.tif" \* MERGEFORMAT
(3)确定通电螺线管上的绕线方向．
INCLUDEPICTURE "25W-1829.tif" INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1829.tif" \* MERGEFORMAT
?典例集训
INCLUDEPICTURE "25W-1830.tif" INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1830.tif" \* MERGEFORMAT
1．如图所示，由通电螺线管的磁感线方向可知，电流表的上端为________接线柱；静止的小磁针的左端为________极．
答案：正　N
2．如图所示，请根据通电螺线管附近静止小磁针的指向，用箭头在A点标出磁感线方向，在B点标出电流方向．
INCLUDEPICTURE "25W-1831.tif" INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1831.tif" \* MERGEFORMAT
答案：如图所示
INCLUDEPICTURE "25W-1832.tif" INCLUDEPICTURE "25W-1832.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1832.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1832.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1832.tif" \* MERGEFORMAT
3．如图所示，请根据小磁针指向确定电源a端的极性，将“＋”或“－”填在(　　)内．
INCLUDEPICTURE "25W-1833.tif" INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1833.tif" \* MERGEFORMAT
答案：＋(图略)
三种电磁现象辨识
?方法指导
四种电磁实验
实验 奥斯特实验 电磁感应实验 探究磁场对通电导线的作用实验 探究电磁铁磁性强弱的影响因素
装置图 INCLUDEPICTURE "25W-1834.tif" INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1834.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1835.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1836.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1837.tif" \* MERGEFORMAT
工作原理 电流的磁效应 电磁感应 通电导体在磁场中受力运动 电流的磁效应
能量转化 — 机械能→电能 电能→机械能 —
影响因素 磁场的方向与电流方向有关 感应电流的方向与磁场的方向、导体切割磁感线的运动方向有关 导体受力的方向与电流的方向、磁场方向有关 电磁铁磁性强弱与电流大小、线圈匝数有关
判断依据 — 电路中无电源 电路中有电源 —
主要应用 电磁铁、电磁继电器 发电机、动圈式话筒 电动机、扬声器 电磁继电器、电磁起重机
?典例集训
4．下列有关电与磁的描述，正确的是(　　)
INCLUDEPICTURE "25W-1838.tif" INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1838.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1839.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1840.tif" \* MERGEFORMAT
甲 乙 丙 丁
A．图甲：根据安培定则，大拇指所指的那端为通电螺线管的S极
B．图乙：电磁继电器就是用永磁体控制工作电路的一种开关
C．图丙：通电线圈在磁场中受力转动，是电动机的工作原理
D．图丁：导线AB左右往复运动过程中，产生的感应电流方向不变
答案：C
5．(多选)如图所示，是各实验现象所揭示的原理或规律与其所对应的应用技术，其中正确的是(　　)
INCLUDEPICTURE "25W-1842.tif" INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1842.tif" \* MERGEFORMAT
A　　　　　　　 　　　B
INCLUDEPICTURE "25W-1843.tif" INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1843.tif" \* MERGEFORMAT
C　　　　　　　　　　D
答案：ACD
INCLUDEPICTURE "实验探究能力提升S.tif" INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT INCLUDEPICTURE "实验探究能力提升S.tif" \* MERGEFORMAT
实验一　探究通电螺线管外部磁场的方向
?探究要点
实验器材的选取及作用 (1)小磁针的作用：显示磁场的方向；(2)在通电螺线管周围不同位置放置小磁针的目的：便于观察不同点的磁场方向；(3)螺线管中插入铁棒的目的：增加螺线管的磁场强度
实验关键操作 (1)在嵌入螺线管的玻璃板上均匀撒些细铁屑，通电后轻敲玻璃板的目的：减小铁屑与玻璃板的摩擦，使铁屑只受磁场作用而排列；(2)电源正负极对调的目的：探究通电螺线管的磁场方向与电流方向是否有关
转换法的应用 (1)根据小磁针的指向判断通电螺线管的极性；(2)通过铁屑的密集程度判断磁场的强弱
实验结论 (1)通电螺线管外部的磁场与条形磁体的磁场相似；(2)磁场方向和电流方向有关
?典例集训
1．实验小组的同学们在“探究通电螺线管外部磁场的特点”实验．
INCLUDEPICTURE "25W-1844.tif" INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1844.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1845.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1846.tif" \* MERGEFORMAT
甲 乙 丙
(1)小明先根据图甲连接好实验装置，在小圆圈位置放置________，目的是____________________；实验时________(选填“能”或“不能”)用大头针代替小磁针．
(2)闭合开关，小磁针的指向如图乙所示，则通电螺线管的左端为________极；小磁针涂黑的一端为________极．(均选填“N”或“S”)
(3)通过观察图乙，可以初步得出结论：通电螺线管外部的磁场与________的磁场相似；为描述磁场而引入的磁感线________(选填“是”或“不是”)真实存在的．
(4)为了研究通电螺线管的磁极性质，小明与小聪一起对螺线管可能的电流方向和绕线方式进行了实验，得到了下列四种情况．实验说明通电螺线管的磁极极性只与它的________有关．
INCLUDEPICTURE "25W-1847.tif" INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1847.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1848.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1849.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1850.tif" \* MERGEFORMAT
A B C D
(5)小聪在嵌入螺线管的玻璃板上均匀撒些细铁屑．通电后轻敲玻璃板，使铁屑与玻璃板微微分离，从而减小铁屑与玻璃板间的________．待细铁屑不再移动后，排列如图丙所示，观察实验现象，这样做的好处是
__________________________________________________________.(合理即可)
(6)小聪进行图丙实验时，若发现通电螺线管的磁场较弱，铁屑规则排列的效果不明显，想要增强通电螺线管周围的磁场强度，在不更换螺线管的前提下，可行的改进措施是________________________________________________________．
(写出一种方法即可)
答案：(1)小磁针　显示磁场方向　不能　(2)S　N　(3)条形磁体　不是　(4)电流方向　(5)摩擦　能更直观地显示通电螺线管内部和外部的磁场分布(或能更直观地显示通电螺线管周围磁场的强弱)　(6)增大螺线管线圈中的电流(或给螺线管中加一根铁棒等)
实验二　探究导体在磁场中运动时产生感应电流的条件
?探究要点
1．实验原理(电磁感应现象).
2．实验装置
INCLUDEPICTURE "25W-1851.tif" INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1851.tif" \* MERGEFORMAT
3．转换法的应用：观察电流计的指针是否偏转来判断是否产生感应电流．
4．控制变量法的应用：
(1)探究感应电流方向与磁场方向的关系：控制导体运动方向不变，改变磁场方向．
(2)探究感应电流方向与导体运动方向的关系：控制磁场方向不变，改变导体运动方向．
5．产生感应电流的条件：①闭合电路；②闭合电路中的一部分导体切割磁感线．
6．影响感应电流方向的因素：①磁场方向；②导体运动方向．
7．影响感应电流大小的因素：①磁场强弱；②导体切割磁感线的速度．
8．感应电流产生过程中的能量转化：机械能转化为电能．
9．实验现象分析及处理方法：
(1)导体在磁场中运动时，电流计不偏转的原因：没有感应电流产生或产生的感应电流很小．
(2)要使电流计偏转明显可采取的措施：加快导体切割磁感线的速度、增加磁场强度、用多匝线圈或多根导线替代单根导线等．
10．电磁感应现象在生活中的应用：发电机、动圈式话筒．
11．实验结论：闭合电路的一部分导体在磁场中做切割磁感线运动产生感应电流，电流的方向与磁场方向和导体运动方向有关．
?典例集训
2．发电机是如何发电的呢？如图所示，同学们在蹄形磁体的磁场中放置一根导线ab，导线ab的两端跟电流表连接，导线跟电流表组成了闭合电路．
INCLUDEPICTURE "25W-1852.tif" INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT INCLUDEPICTURE "25W-1852.tif" \* MERGEFORMAT
(1)实验中可以通过电流表的指针是否________来判断电路中是否有感应电流产生；通过电流表指针的偏转方向来判断______________；通过指针的____________来判断感应电流的大小．
(2)当导线ab悬挂起来静止后，电流表指针不偏转，说明电路中________(选填“有”或“无”)感应电流产生．
(3)小芳无意间碰到导线ab，导线ab晃动起来，小明发现电流表指针发生了偏转，就说：“让导体在磁场中运动就可产生电流．”但小芳说：“不一定，还要看导体怎样运动．”为验证猜想，他们继续探究，并把观察到的现象记录如下：
序号 磁体摆放方向 导线ab运动方向 电流表指针偏转情况
1 N极在上 竖直上下运动 不偏转
2 水平向左运动 向右偏转
3 水平向右运动 向左偏转
4 N极在下 竖直上下运动 不偏转
5 水平向左运动 向左偏转
6 水平向右运动 向右偏转
分析实验现象与数据，可得出小芳的观点是________(选填“正确”或“错误”)的．
(4)比较第2、3次实验现象发现，产生的电流的方向跟____________________有关；比较第3、6次实验现象发现，产生的电流的方向还跟________有关．
(5)在整理器材时，小明撤去蹄形磁体，有同学发现指针又偏转了．他们再重复刚才的操作，发现电流表的指针会偏转．请教老师后得知，不论是导体运动还是磁体运动，只要闭合电路的一部分导体在________中做________________运动，电路中就会产生感应电流．这最早由英国物理学家________发现．
(6)电路产生感应电流的过程中将________能转化为电能，利用此原理可用来制造________(选填“电动机”或“发电机”).
(7)本实验中________(选填“可以”或“不可以”)用小灯泡代替电流表，原因是_________________________________________________________________________________________________________________________________________.
(8)想要探究磁场对通电导体的作用，只需将________更换为________．
答案：(1)偏转　感应电流的方向　偏转角度大小　(2)无　(3)正确　(4)导体运动方向　磁场方向　(5)磁场　切割磁感线　法拉第　(6)机械　发电机　(7)不可以　感应电流较小时，小灯泡不一定会发光，并且不能反映电流的方向　(8)电流表　电源
INCLUDEPICTURE "真题在线明晰考向S.tif" INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT INCLUDEPICTURE "真题在线明晰考向S.tif" \* MERGEFORMAT
1．(2021·T1)下图是我国古代四大发明之一的指南针——司南，静止时它的长柄指向地理的________方．在11世纪，我国宋代学者________就发现了地理两极和地磁两极并不重合，这个发现比西方早了400多年．
INCLUDEPICTURE "26JXWL-103.tif" INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-103.tif" \* MERGEFORMAT
答案：南　沈括
2．(2024·T4)在大力倡导节能环保、践行低碳生活的新时代，新能源汽车越来越普及．其中新能源电动汽车中的电动机利用通电线圈在________中受力转动，把________能转化为机械能，从而驱动汽车行驶．
答案：磁场　电
3．(2022·T4)如图所示，这是某同学在科技节上展示的作品结构图．该作品的工作原理是通电线圈在________中受力转动，它就是一个自制的________机模型图．
INCLUDEPICTURE "26JXWL-104.tif" INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-104.tif" \* MERGEFORMAT
答案：磁场　电动
4．(2023·T4)如图所示，卸下家用微型风扇的插头后，将两根导线分别与灵敏电流计连接起来，用力转动风扇叶子，看到灵敏电流计的指针偏转，这是________________现象，此过程中机械能转化为________能．
INCLUDEPICTURE "26JXWL-105.tif" INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-105.tif" \* MERGEFORMAT
答案：电磁感应　电
5．(2021·T11)下图是燃油汽车启动装置的电路简图．汽车启动时，需将钥匙插入仪表板上的钥匙孔并旋转，则下列分析正确的是(　　)
INCLUDEPICTURE "26JXWL-106.tif" INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-106.tif" \* MERGEFORMAT
A．旋转钥匙相当于闭合开关
B．电磁铁是利用电流的热效应来工作的
C．电磁铁通电后电磁铁的上端为S极
D．电动机工作时将电能全部转化为机械能
答案：A
6．(2019·T15)如图所示，这是小安同学自制的一个实验装置，他把带绝缘层的导线绕在塑料管外，导线两端连接着小灯泡，形成闭合电路，管内封闭一个强磁体，沿图中所示方向来回快速摇动装置，小灯泡发光．以下说法正确的是(　　)
INCLUDEPICTURE "26JXWL-107.tif" INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-107.tif" \* MERGEFORMAT
A．灯丝中电流方向保持不变
B．实验现象表明电能够生磁
C．该现象属于电磁感应现象
D．此装置与电动机原理相同
答案：C
7．(2022·T12)如图所示，这是某同学自制的简易电磁锁原理图．闭合开关S，滑片P向左移动，使静止在水平桌面的条形磁体滑动，打开门锁．下列说法正确的是(　　)
INCLUDEPICTURE "26JXWL-108.tif" INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-108.tif" \* MERGEFORMAT
A．通电后电磁铁a端为S极
B．滑片向左移动的过程中电磁铁的磁性增强
C．条形磁体在滑动过程中受到向左的摩擦力
D．条形磁体在滑动过程中受到的摩擦力变小
答案：B
8．(2024·T12)如图所示，通电螺线管旁的小磁针分别静止在图示位置．请科学推断，最终决定通电螺线管极性的是(　　)
INCLUDEPICTURE "26JXWL-109.tif" INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-109C．tif" \* MERGEFORMAT
甲 乙 丙 丁
A．电源正负极的接法
B．螺线管导线的环绕方向
C．小磁针静止时N极的指向
D．螺线管中电流的方向
答案：D
9．(2020·T25，节选)探究磁与电的联系．如图甲所示，是灵敏电流计的内部结构．小红同学参加课外实践活动，发现灵敏电流计内部结构与电动机、发电机内部结构类似．出于好奇，她利用如图乙所示的装置进行了下面的实验．
【进行实验】用手拨动其中一个灵敏电流计指针的同时，另一个灵敏电流计的指针也发生了偏转．
【交流】拨动右侧灵敏电流计的指针时，表内线圈在磁场中________________运动，产生了感应电流．于是，左侧灵敏电流计内的线圈同时也会有电流，它在________中受到力的作用，带动指针偏转起来．此时的右侧灵敏电流计相当于________机．
INCLUDEPICTURE "26JXWL-110.tif" INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-110A．tif" \* MERGEFORMAT
甲 乙
答案：做切割磁感线　磁场　发电
10．(2025·T20)探究通电螺线管外部磁场的方向
某组同学通过探究，已了解通电螺线管的两端相当于条形磁体的两极，它们的极性可以用小磁针的指向来判定后，接着探究通电螺线管两端的极性由什么因素决定．
【猜想】
A．可能由螺线管的绕向决定
B．可能由电源正负极的接法决定
C．可能由螺线管中电流的方向决定
(注解：螺线管两接线柱和电源正负极的接法简称电源正负极的接法)
INCLUDEPICTURE "26JXWL-327.tif" INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-327.tif" \* MERGEFORMAT
【证据】用________将如图所示的器材连接成电路，把小磁针放在螺线管两端，闭合开关，观察并记录小磁针静止时N极的指向、螺线管的绕向、电源正负极的接法、螺线管中电流的方向．如图所示，是本组同学用画图的方法呈现出的四次实验现象．
INCLUDEPICTURE "26JXWL-328.tif" INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328.tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328A．tif" \* MERGEFORMAT
甲 乙
INCLUDEPICTURE "26JXWL-328B．tif" INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328B．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT INCLUDEPICTURE "26JXWL-328C．tif" \* MERGEFORMAT
丙 丁
【解释】
(1)观察分析图甲、乙两图，螺线管的绕向相同，通电螺线管的同一端磁极________；
(2)观察分析图甲、丙两图，电源正负极的接法相同，通电螺线管的同一端磁极________；
(3)观察分析图________两图，螺线管中电流的方向相同，通电螺线管的同一端磁极相同；
(4)分析以上证据可知，通电螺线管的极性由螺线管中________决定，而不决定于________，也不决定于________________．
答案：【证据】导线
【解释】(1)不同
(2)不同
(3)甲、丁(或乙、丙)
(4)电流的方向　螺线管的绕向　电源正负极的接法(后两空可互换顺序)

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