This set of Analog Communication Multiple Choice Questions & Answers (MCQs) focuses on “Power Relations in AM Waves”.

1. For 100% modulation, power in each sideband is ________ of that of carrier.

a) 50%

b) 70%

c) 60%

d) 25%

2. Overmodulation results in ________________

a) Distortion

b) Weakens signal

c) Strengthens the signal

d) provides immunity to noise

3. Calculate power in each sideband, if power of carrier wave is 176W and there is 60% modulation in amplitude modulated signal?

a) 13.36W

b) 52W

c) 67W

d) 15.84W

4. The maximum power efficiency of an AM modulator is?

a) 25%

b) 33%

c) 66%

d) 100%

5. For getting 100% modulation, carrier amplitude should ________

a) exceed signal amplitude

b) be equal to signal amplitude

c) be lesser than signal amplitude

d) be equal to 0

6. Noise performance of a square law demodulator of AM signal is?

a) Better than that of synchronous detector

b) Weaker than that of synchronous detector

c) Better than that of envelope detector

d) Weaker than that of envelope detector

7. For 100% modulation, total power is?

a) same as the power of unmodulated signal

b) twice as the power of unmodulated signal

c) four times as the power of unmodulated signal

d) one and half times as the power of unmodulated signal

8. An AM signal is represented by x(t) = (30 + 2Sin(700πt)) Cos(2πt x 10^{2}t)V. Carrier power of the wave is?

a) 555W

b) 675W

c) 450W

d) 310W

9. An AM signal is represented by x(t) = (30 + 2Sin(700πt)) Cos(2πt x 10^{2}t)V. What is its sideband power?

a) 4W

b) 1W

c) 3W

d) 2W

10. An AM signal is represented by x(t) = (30 + 2Sin(700πt)) Cos(2πt x 10^{2}t)V. What is the value of modulation index?

a) 0.7

b) 0.066

c) 0.341

d) 0.916

11. An AM signal is represented by x(t) = (30 + 2Sin(700πt)) Cos(2πt x 10^{2}t)V. Find the total power of amplitude modulated wave?

a) 453W

b) 675W

c) 789W

d) 451W