1.选择题- (共4题)
3.阅读下面短文，根据短文内容回答问题。
Many would agree that when we think of Christmas, we probably think of gifts, Christmas trees and Santa Claus. But behind all these things lies the true meaning of Christmas: the importance of sharing and giving love and joy to people around us. The story in A Christmas Carol is perhaps the best example of this.
A Christmas Carol is a famous novel written by Charles Dickens. It is about an old man named Scrooge. He only thinks about himself and doesn't treat others nicely. He just cares about whether he can make more money. And he hates Christmas. One Christmas Eve, Scrooge sees the ghost of Jacob Marley, his dead business partner. Marley used to be just like Scrooge, so he was punished after he died. He warns Scrooge to change his ways if he doesn't want to end up like him. He also tells Scrooge to expect three spirits to visit him.、
That night, three ghosts visit Scrooge. First, the Ghost of Christmas Past takes him back to his childhood and reminds Scrooge of his happier days as a child. Then the second spirit, the Ghost of Christmas Present, takes him to see how others are spending Christmas this year. Everyone is happy, even poor people. The last one, the Ghost of Christmas Yet to Come, takes him to the future. He sees that he is dead but nobody cares. Scrooge is so scared that he wakes up in his bed and finds out it is already the next morning on Christmas Day!
He decides to change his life and promises to be a better person. He happily celebrates Christmas with his relatives. He also gives gifts to people in need. He now treats everyone with kindness and warmth, spreading love and joy everywhere he goes. And that is the true spirit of Christmas!
Many would agree that when we think of Christmas, we probably think of gifts, Christmas trees and Santa Claus. But behind all these things lies the true meaning of Christmas: the importance of sharing and giving love and joy to people around us. The story in A Christmas Carol is perhaps the best example of this.
A Christmas Carol is a famous novel written by Charles Dickens. It is about an old man named Scrooge. He only thinks about himself and doesn't treat others nicely. He just cares about whether he can make more money. And he hates Christmas. One Christmas Eve, Scrooge sees the ghost of Jacob Marley, his dead business partner. Marley used to be just like Scrooge, so he was punished after he died. He warns Scrooge to change his ways if he doesn't want to end up like him. He also tells Scrooge to expect three spirits to visit him.、
That night, three ghosts visit Scrooge. First, the Ghost of Christmas Past takes him back to his childhood and reminds Scrooge of his happier days as a child. Then the second spirit, the Ghost of Christmas Present, takes him to see how others are spending Christmas this year. Everyone is happy, even poor people. The last one, the Ghost of Christmas Yet to Come, takes him to the future. He sees that he is dead but nobody cares. Scrooge is so scared that he wakes up in his bed and finds out it is already the next morning on Christmas Day!
He decides to change his life and promises to be a better person. He happily celebrates Christmas with his relatives. He also gives gifts to people in need. He now treats everyone with kindness and warmth, spreading love and joy everywhere he goes. And that is the true spirit of Christmas!
2.单选题- (共2题)
5.
如图所示，闭合矩形线框abcd位于磁感应强度为B的匀强磁场中，ad边位于磁场边缘，线框平面与磁场垂直，ab、ad边长分别用L1、L2表示，若把线圈沿v方向匀速拉出磁场所用时间为△t，则通过线框导线截面的电量是( )
A． | B． | C． | D．BL1L2 |
6.
如图（甲）所示，理想变压器原副线圈的匝数比为10:1，b是原线圈的中心抽头，电压表和电流表均为理想电表，除R以外其余电阻不计。从某时刻开始单刀双掷开关掷向a，在原线圈两端加上如图（乙）所示交变电压，则下列说法中正确的是：( )
A．该交变电压瞬时值表达式为 (V) |
| B．滑动变阻器触片向上移，电压表示数不变，电流表的示数变大 |
C． s时，电压表的读数为31. 1V |
| D．单刀双掷开关由a扳到b，电压表和电流表的示数都变大 |
3.多选题- (共2题)
7.
如图所示的电路中，L是自感系数很大的线圈，但其自身的电阻几乎为零。
是两个相同的灯泡，下列说法中正确的是（）
是两个相同的灯泡，下列说法中正确的是（）| A．开关S由断开变为闭合，同时发光，之后亮度不变 |
B．开关S由断开变为闭合， 立即发光，之后又逐渐熄灭 |
| C．开关S由闭合变为断开的瞬间，同时熄灭 |
| D．开关S由闭合变为断开的瞬间，再次发光，之后又逐渐熄灭 |
8.
为了减少输电线路中电力损失，发电厂发出的电通常是经过升压变电站升压后通过远距离输送，再经过降压变电站将高压变为低压．某降压变电站将电压U0＝11000sin100πt(V)的交流电降为220 V供居民小区用电，则降压变电站变压器( )
| A．原、副线圈匝数比为50∶1 |
| B．副线圈中电流的频率是50 Hz |
| C．副线圈中电流的频率是1 Hz |
| D．输入原线圈的电流等于居民小区各用电器电流的总和 |
4.填空题- (共1题)
9.
边长为a的正方形，内部充满匀强磁场，方向垂直纸面向里，如图所示，一束电子以不同的水平速度从左上角射入磁场后，分别从A处和C处射出，则从A处和C处射出的粒子速度之比为vA：vC=____；所经历的时间之比tA：tC=____。
5.解答题- (共3题)
10.
（13分）在如图所示的平面直角坐标系中，存在一个半径R＝0.2 m的圆形匀强磁场区域，磁感应强度B＝1.0 T，方向垂直纸面向外，该磁场区域的右边缘与y坐标轴相切于原点O点．y轴右侧存在电场强度大小为E＝1.0×104 N/C的匀强电场，方向沿y轴正方向，电场区域宽度l＝0.1 m．现从坐标为(－0.2 m，－0.2 m)的P点发射出质量m＝2.0×10－9 kg、带电荷量q＝5.0×10－5 C的带正电粒子，沿y轴正方向射入匀强磁场，速度大小v0＝5.0×103 m/s.（粒子重力不计）．
(1)求该带电粒子射出电场时的位置坐标；
(2)为了使该带电粒子能从坐标为(0.1 m，－0.05 m)的点回到电场，可在紧邻电场的右侧一正方形区域内加匀强磁场，试求所加匀强磁场的磁感应强度大小和正方形区域的最小面积．
(1)求该带电粒子射出电场时的位置坐标；
(2)为了使该带电粒子能从坐标为(0.1 m，－0.05 m)的点回到电场，可在紧邻电场的右侧一正方形区域内加匀强磁场，试求所加匀强磁场的磁感应强度大小和正方形区域的最小面积．
11.
如图所示，质量为m、边长为L的正方形线框，从有界的匀强磁场上方由静止自由下落，线框电阻为R，匀强磁场的高度为H，（L<H），磁感应强度为B，线框下落过程中ab边与磁场边界平行且保持水平。已知ab边刚进入磁场时和ab边刚穿出磁场时线框都做减速运动，加速度大小都为
．求：
（1）ab边刚进入磁场时和ab边刚出磁场时的速度大小；
（2）cd边刚进入磁场时，线框的速度大小；
（3）线框进入磁场的过程中，产生的热量．
．求：（1）ab边刚进入磁场时和ab边刚出磁场时的速度大小；
（2）cd边刚进入磁场时，线框的速度大小；
（3）线框进入磁场的过程中，产生的热量．
12.
如图所示，在一个由x轴和曲线为边界包围的空间中存在匀强磁场，曲线方程为
（单位：m）(
)。磁场方向垂直纸面向里，磁感应强度大小为
。有一ab边与x轴重合的正方形金属线框在水平拉力F作用下以1.0m/s速度水平向右匀速运动，线框边长为0.4m，线框电阻为0.1
，试求：
（1）在线框通过磁场区域的过程中，拉力F的最大瞬时功率是多少？
（2）在下面坐标图中画出线框产生的电流随时间变化图象（取
方向为电流正方向）。
（3）线框经过磁场区域的整个过程，拉力F做多少功？
（单位：m）()。磁场方向垂直纸面向里，磁感应强度大小为。有一ab边与x轴重合的正方形金属线框在水平拉力F作用下以1.0m/s速度水平向右匀速运动，线框边长为0.4m，线框电阻为0.1，试求：（1）在线框通过磁场区域的过程中，拉力F的最大瞬时功率是多少？
（2）在下面坐标图中画出线框产生的电流随时间变化图象（取
方向为电流正方向）。（3）线框经过磁场区域的整个过程，拉力F做多少功？
6.实验题- (共1题)
试卷分析
-
【1】题量占比
选择题:(4道)
单选题:(2道)
多选题:(2道)
填空题:(1道)
解答题:(3道)
实验题:(1道)
-
【2】：难度分析
1星难题：0
2星难题：0
3星难题：0
4星难题：1
5星难题：0
6星难题：3
7星难题：0
8星难题：5
9星难题：0