GROL Electrical Principles and Units 5

Question 1

A power amplifier has a 1-watt input and a 100-watt output. What is the power gain in dB?

Accepted Answer

20 dB

Answer

10 dB

Answer

30 dB

Answer

100 dB

Question 2

A voltage gain of 10 times corresponds to how many dB?

Accepted Answer

20 dB

Answer

10 dB

Answer

30 dB

Answer

40 dB

Question 3

A transformer has 1000 primary turns and 100 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?

Accepted Answer

12 V

Answer

1.2 V

Answer

120 V

Answer

1200 V

Question 4

A step-down transformer has 1000 primary turns and 100 secondary turns. If the secondary delivers 10 A to a load, what is the primary current (assume 100% efficiency)?

Accepted Answer

1 A

Answer

10 A

Answer

100 A

Answer

0.1 A

Question 5

What is the time constant of a series RC circuit with R = 10 kΩ and C = 0.1 μF?

Accepted Answer

1 ms

Answer

0.1 ms

Answer

10 ms

Answer

100 ms

Question 6

After one time constant, a capacitor in an RC charging circuit has charged to approximately what percentage of the supply voltage?

Accepted Answer

63%

Answer

37%

Answer

50%

Answer

100%

Question 7

Skin effect in RF conductors causes current to:

Accepted Answer

Flow primarily on the outer surface of the conductor

Answer

Flow uniformly throughout the conductor cross-section

Answer

Flow only through the center of the conductor

Answer

Reverse direction at each half-cycle