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WorksheetsAC current 交流电
Total questions: 12
Worksheet time: 48mins
A heater is rated as 230 V, 10 kW. The value 230 V refers to
一电热器标示 230 V, 10 kW。230 V 指的是
average voltage
平均电压
r.m.s voltage
r.m.s电压
peak voltage
电压峰值
An electric current that continually reverses direction over time is known as a(n)
持续改变方向的电流称为
direct current 直流电
alternating current 交流电
steady current 恒定电流
reverse current 反向电流
Which of the following is not an alternating current?
下列哪个图不是交流电？
一交流电的峰值为 2 A，电流的有效值是
The peak value of an ac current is 2 A, the effective value of the current is
0.707 A
1.414 A
0.5 A
1 A
一交流电通过电阻 10 Ω 的灯泡，电压有效值为 5 V，求经过灯泡的最大电流。
An AC current pass through a 10 Ω bulb. The effective value of the voltage is 5 V, find the maximum current that pass through the bulb.
2 A
0.5 A
0.707 A
0.354 A
In a pure inductive ac circuit, the current is
在一个纯电感交流电路中，电流
in phase with voltage
与电压同相（同步）
lags behind the voltage by 90°
比电压落后 90°
leads the voltage by 90°
比电压超前 90°
lead or lag voltage by 90°
比电压超前或落后 90°
设磁场的磁感应强度为 0.2 T，单匝线圈长 10 cm，宽 5 cm，线圈在磁场中转速为 10 rad s-1，求线圈转动时感应电动势的峰值。
Suppose the magnetic induction of a magnetic field is 0.2 T, a single-turn coil is of length 10 cm and width 5 cm. The angular speed of the coil in the magnetic field is 10 rad s-1. Find the peak value of the induced electromotive force when the coil rotates.
0.01 V
0.1 V
10 V
100 V
Capacitive reactance is more when _______________
当_______________，容抗将增大
capacitance is less and frequency of supply is less
电容减少，电源频率减少
capacitance is less and frequency of supply is more
电容减少，电源频率增加
capacitance is more and frequency of supply is less
电容增加，电源频率减少
capacitance is more and frequency of supply is more
电容增加，电源频率增加
把一个 0.7 H 的电感线圈接在 50 Hz 的交流电上，感抗是多少？
What is the inductive reactance of a 0.7 H inductive coil connected to 50 Hz AC?
219.9 Ω
0.0045 Ω
35 Ω
0.029 Ω
The total impedance of a series 50 Hz RLC circuit with L = 20 mH, C = 0.002 F, and R = 90 Ω is
某 50 Hz 串联 RLC 电路中，L = 20 mH、C = 0.002 F 、 R = 90 Ω 的总阻抗为
6.28 Ω
1.59 Ω
90 Ω
90.12 Ω
一变压器的原线圈 1000 匝，副线圈 250 匝，若原线圈与 200 V 交流电连接，副线圈的电压是多少？
The primary coil of a transformer is 1000 turns and the secondary coil is 250 turns. If the primary coil is connected to 200 V AC, what is the voltage of the secondary coil?
50 V
800 V
200 V
100 V
下列哪个电子元件可用于将交流电转成直流电？
Which of the following electronic components can be used to convert AC to DC?
二极管 Diode
三极管 transistor
变压器 transformer
电容器 capacitor
