Free Printable Week 6 Quiz in EE 200

1.

Calculate the energy stored in a 22 µF capacitor when it is charged to 120 V?

a)

290 mJ

b)

317 mJ

c)

158 mJ

d)

3.17 mJ

2.

Two series capacitors (one is 2 µF, the other of unknown value) are charged from a 24 V source. The 2-µF capacitor is charged to 16 V and the other to 8 V. The value of the unknown capacitor is _____.

a)

1 µF

b)

4 µF

c)

2 µF

d)

8 µF

3.

An inductor, a 1-kΩ resistor, and a switch are connected in series across a 6 V battery. At the instant the switch is closed, the inductor voltage is

a)

0 V

b)

6 V

c)

4 V

d)

12 v

4.

A 220- Ω resistor is in series with a 2.2-µF capacitor. The time constant is __________.

a)

48 µs

b)

2.42 µs

c)

484 µs

d)

24 µs

5.

The winding resistance of a coil can be increased by

a)

using a thinner wire .

b)

increasing the number of turns

c)

changing the core material.

d)

increasing the number of turns or using thinner wire.

6.

The current through a 120 mH coil is changing at a rate of 150 mA/s. The voltage induced across the coil is_____.

a)

1.8 mV

b)

180 mV

c)

18 mV

d)

1.25 V

7.

An 18 V power supply is connected across a coil with a winding resistance of 180 Ω. Current flow in the coil is ________.

a)

1 mA

b)

100 mA

c)

10 mA

d)

1 A

8.

A switch, a 220-Ω resistor, and a 60 mH inductor are in series across a 20 V battery. What is the current through the inductor two time constants after the switch is closed?

a)

91 mA

b)

57 mA

c)

79 mA

d)

400 mA

9.

A 320 𝜇H coil is in series with a 3.3 k-Ω resistor. How long does it take for current to build up to its full value?

a)

0.4848 s

b)

0.4848 𝜇s

c)

0.4848 ms

d)

4.848 𝜇s

10.

Five inductors are connected in series. The lowest value is 8 μH. If the value of each inductor is twice that of the preceding one, and if the inductors are connected in order of ascending values, the total inductance is _______.

a)

8 H

b)

64 μH

c)

32 μH

d)

248 μH

11.

The inductance of an iron-core coil decreases if

a)

the number of turns is decreased.

b)

the iron core is removed.

c)

the length of the coil decreases.

d)

The conductor material is changed

12.

The following coils are in parallel: 75 𝜇H, 40 𝜇H, 25 𝜇H, and 15 𝜇H. The total inductance is approximately ____ 𝜇H.

a)

6.9

b)

2.2

c)

14

d)

155

13.

When the current through an inductor is cut in half, the amount of energy stored in the electromagnetic field ___________________.

a)

Is quartered

b)

Doubled

c)

Quadruples

d)

Does not change

14.

Faraday's law states that the magnitude of the e.m.f. induced in a circuit is proportional to the magnitude of the flux linking the circuit.

a)

true

b)

false

15.

The current in a 25 mH inductor changes at a constant rate of 7 A/s. What voltage is induced across this coil?

a)

3.57 mV

b)

350 mV

c)

175 mV

d)

1.75 V

16.

Calculate the inductance of this arrangement.

a)

20 mH

b)

90 mH

c)

30 mH

d)

120 mH

17.

Calculate the inductance of this arrangement.

a)

20 mH

b)

90 mH

c)

30 mH

d)

120 mH

18.

A 22-µF capacitor has a charge of 250-µC stored in it. What is the voltage across the capacitor?

a)

0.88 V

b)

11.4 V

c)

5.5 V

d)

15.5 V

19.

A capacitor has plates 15 x 30 mm which have a separation of 10 mm. If the gap between the plates filled with air, what is its capacitance? The relative permitivity of air is 1.

a)

0.400 pF

b)

0.400 µF

c)

0.400 nF

d)

0.400 mF

20.

What is the capacitance of the capacitor described in the last question if the gap between the plates is filled with a dielectric with a relative permittivity of 200?

The previous question is:

A capacitor has plates 15 x 30 mm which have a separation of 10 mm. If the gap between the plates filled with air, what is its capacitance?

a)

2 pF

b)

80 nF

c)

80 µF

d)

80 pF

21.

The circuit in (a) above shows an arrangement that applies a step voltage across a combination of a resistor and an initially unexcited inductor. What quantity is shown plotted against time in the graph in (b)?

a)

The inductor voltage V_L

b)

The current I.

22.

What energy is stored in an inductor of energy is stored in an inductor of 40 mH when a current of 8 A is passing through it?

a)

1.6 mJ

b)

160 mJ

c)

128 mJ

d)

1.28 J

23.

A 4.7-MΩ resistor is in series with a 0.015-µF capacitor. The combination is across a 12 V source. How long does it take the capacitor to fully charge?

a)

35 ms

b)

3.5 ms

c)

352.5 ms

d)

70.5 ms

24.

What is the effective capacitance of the following arrangement?

a)

0.5 µF

b)

4.5 µF

c)

2 µF

d)

9 µF

25.

What is the effective capacitance of the following arrangement?

a)

0.5 µF

b)

4.5 µF

c)

2 µF

d)

9 µF

26.

In a capacitor, the relationship between the current and the voltage can be written as i = C dV/dt.

a)

true

b)

false

27.

An uncharged capacitor and a 1 kΩ resistor are connected in series with a switch and a 6 V battery. At the instant the switch is closed, the voltage across the capacitor is __________.

a)

0 V

b)

2 V

c)

1 V

d)

6 V

28.

An uncharged capacitor and a 1 kΩ resistor are connected in series with a switch and a 6 V battery. At the instant the switch is closed, the voltage across the capacitor when it is fully charged is

a)

6 V

b)

12 V

c)

-6 V

d)

-0 V

29.

The circuit in (a) above shows an arrangement that applies a step voltage across a combination of a resistor and an initially uncharged capacitor. What quantity is shown plotted against time in the graph in (b)?

a)

The capacitor voltage V_C

b)

The current I.

30.

Calculate the inductance of the air-filled coil shown here. The permeability of air is 4 $\pi$ x 10 ^ -7 H/m.

a)

176 nH

b)

87 µH

c)

35 µH

d)

123 µH

31.

The vertical axis of a waveform graph is usually marked in units of time.

a)

true

b)

false

32.

One half-cycle is also known as an alternation.

a)

true

b)

false

33.

One alternation per second is equal to 2 Hz.

a)

true

b)

false

34.

The average value of a sine wave is smaller than the rms value.

a)

true

b)

false

35.

The horizontal axis of a waveform graph is usually marked in units of voltage or current.

a)

true

b)

false

36.

The magnitude of AC voltage is easier to change than the magnitude of DC voltage.

a)

true

b)

false

37.

There are 180 electrical degrees in one alternation.

a)

true

b)

false

38.

Effective, or rms, values of alternating current produce the same heating effect as the same value of direct

current.

a)

true

b)

false

39.

The rms or effective value of 0.637 x the maximum value.

a)

true

b)

false

40.

A conductor rotating in a perfect circle at constant speed in a uniform magnetic field produces a sine wave.

a)

true

b)

false

41.

A (a) is produced when values of voltage and time are plotted on a graph.