GROL Electrical Principles and Units 3

Question 1

What is the capacitive reactance of a 100 pF capacitor at 10 MHz?

Accepted Answer

159 Ω

Answer

Xc = 1/(2πfC) = 1/(2π × 10⁷ × 10⁻¹⁰) ≈ 159 Ω.

Question 2

A coil has inductive reactance of 100 Ω at 1 MHz. What is its inductance?

Accepted Answer

15.9 μH

Answer

L = XL/(2πf) = 100/(2π × 10⁶) ≈ 15.9 μH.

Question 3

Two 10 μF capacitors are connected in series. What is the total capacitance?

Accepted Answer

5 μF

Answer

For two equal capacitors in series, Cs = C/2 = 10/2 = 5 μF.

Question 4

Two inductors of 100 μH and 200 μH are connected in series with no mutual coupling. What is the total inductance?

Accepted Answer

300 μH

Answer

Series inductors (no mutual coupling) add directly: 100 + 200 = 300 μH.

Question 5

What happens to capacitive reactance as frequency increases?

Accepted Answer

It decreases

Answer

Since Xc = 1/(2πfC), reactance is inversely proportional to frequency and decreases as frequency rises.

(GROL) General Radiotelephone Operator License Practice Test