Physics 222 Worksheet: Chapter 21, Electromagnetic Induction, Inductance
1) Induced voltage is proportional to
a) magnetic flux
b) magnetic field times area
c) magnetic flux times area
d) the rate of change of magnetic flux
2) Doubling the number of loops of wire in a coil causes what change in the induced voltage?
a) The induced voltage is four times as much.
b) The induced voltage is twice as much.
c) The induced voltage is not changed.
d) The induced voltage is one half as much.
3) Which of the following devices does not depend on electromagnetic induction in order to work?
a) generator
b) capacitor
c) transformer
d) coil
4) v s/A is the same as a(n)
a) ohm
b) farad
c) watt
d) henry
5) A transformer that has more turns on the secondary than on the primary will:
a) step up voltage and current.
b) step down voltage and current.
c) step up voltage and step down current.
d) step down voltage and step up current.
6) Commercial electric power is distributed in the form of AC rather than DC because:
a) electric motors require AC.
b) resistors use less power with AC.
c) transformers are available to step up and step down AC voltage but not DC.
d) capacitors transmit only AC, not DC.
7) The current in the figure below is decreasing. Therefore the induced current in the loop will:
a) flow clockwise
b) flow counterclockwise
c) be zero
d) (this one hurt my wrist)
8) In the figure below a conducting rod is moving as shown across conducting rails. The magnetic field is directed into the figure. The induced current in the rectangular loop will:
a) flow clockwise
b) flow counterclockwise
c) be zero
Ans: 1-d, 2-b, 3-b, 4-d, 5-c, 6-c, 7-b, 8-b
Physics 222
Worksheet: Electromagnetic Induction
1) In the figure, B is increasing. The direction of the induced current in the loop is:
a) clockwise.
b) counterclockwise.
2) In the figure, B is decreasing. The direction of the induced current in the loop is:
a) clockwise.
b) counterclockwise.
3) In the figure, B is increasing. The direction of the induced current in the loop is:
a) clockwise.
b) counterclockwise.
4) In the figure, B is decreasing. The direction of the induced current in the loop is:
a) clockwise.
b) counterclockwise.
Ans: 1-a, 2-b, 3-b, 4-a
Physics 222 Worksheet: Chapter 21, AC Circuits, EM Waves
1) Whenever the frequency in an AC series circuit increases, the ____ will also increase.
a) current
b) inductive reactance
c) capacitive reactance
d) impedance
2) Which of the following is not true about a circuit operating at its resonant frequency?
a) The current is at a maximum.
b) The impedance is at a maximum.
c) The inductive and capacitive reactances are equal.
d) The phase angle is zero.
3) In a circuit the resistance is 400 W, the inductive reactance is 900 W, and the capacitive reactance is 600 W. The impedance is
a) 1900 W
b) 700 W
c) 500 W
d) 100 W
4) In a capacitor
a) the voltage leads the current by 90°
b) the current leads the voltage by 90°
c) the voltage and current are 180° out of phase
d) the voltage and current are in phase
5) Which of the following creates electromagnetic waves?
a) charges at rest
b) charges moving at constant speed
c) accelerating charges
d) DC current
6) Electromagnetic waves with low frequency
a) travel faster than electromagnetic waves with a higher frequency.
b) travel more slowly than electromagnetic waves with a higher frequency.
c) have a shorter wavelength than electromagnetic waves with a higher frequency.
d) have a longer wavelength than electromagnetic waves with a higher frequency.
7) Identify the circuit type represented by each of the impedance vs. frequency graphs.
a) Circuit with inductance and resistance only. (RL circuit) _________
b) Circuit with capacitance and resistance only. (RC circuit) _________
c) Circuit with capacitance, inductance, and resistance. (RLC circuit) _________
Ans: 1-b, 2-b, 3-c, 4-b, 5-c, 6-d, 7a-Fig 2, 7b-Fig 1, 7c-Fig 3