 # Class 12 Physics Chapter 15 Communication System MCQs

Introducing to you the latest Class 12 Physics MCQs for Chapter 15, along with their answers. The MCQ Questions with answers for Class 12 Physics, designed as per the latest exam pattern, will help students improve their mastery over the chapter and help them score adequate marks in board exams.

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## Class 15 Communication System MCQs

Check the multiple-choice questions for the 12th Class Physics Communications System Chapter. Each MCQ will have four options here, out of which only one is correct. Students have to pick the correct option and check the answer provided here.

1. What purpose does the transducer serve?

1. It converts sound signal to electrical signal
2. It converts the electrical signal to a sound signal
3. (c) It converts electrical signals to magnetic form
4. (d) It converts sound signal to magnetic signal

Answer: (b) It converts an electrical signal to a sound signal.

Explanation: A transducer converts an electrical signal to a sound signal.

2. Which of the following is a drawback of the amplitude modulation?

1. Noise Reception
2. Low Efficiency
3. Low Operating range
4. All of the above

Answer: (d) All of the above

Explanation: Noise Reception, low efficiency and low operating range are the drawbacks of amplitude modulation.

3. Why audio signals cannot be transmitted?

1. Because it has more noise
2. The length of the transmitting antenna is very small
3. The length of the transmitting antenna is very large
4. The signal cannot be amplified for distance communication

Answer: (c) The length of the transmitting antenna is very large

Explanation: Audio signals cannot be transmitted because the length of the transmitting antenna is very large.

4. What happens to the satellite speed when the height of the satellite orbit gets lower?

1. Increases
2. Decreases
3. Remains same
4. Both (a) and (b)

Explanation: The satellite speed decreases as the height of the satellite orbit gets lower.

5. What happens when the frequency deviation is doubled in FM?

1. Modulation is doubled
2. Modulation is halved
3. Carrer swing is halved
4. The modulation index is decreased

Explanation: When the frequency deviation is doubled, the modulation doubles.

6. What happens if the transmission path in PCM is very long?

1. Pulse amplitude is increased
2. Pulse spacing is reduced
3. Pulse width is increased
4. Repeater stations are used

Answer: (d) Repeater stations are used

Explanation: Repeater stations are used in the transmission path in PCM is very long.

7. Television signals are

1. Amplitude modulated
2. Frequency modulated
3. Phase modulated
4. Both frequency and amplitude modulated

Answer: (d) Both frequency and amplitude modulated

Explanation: Television signals are both frequency and amplitude modulated.

8. What happens when the radio wave reaches the ionizing medium?

1. Will bend towards normal
2. Will bend away from the normal
3. Will follow a straight path
4. None of these

Answer: (a) Will bend away from the normal

Explanation: The radio waves reaching the ionizing medium will bend away from the normal.

9. The summation of three sinusoidal waves is equal to

1. AM Waves
2. FM Waves
3. Both (a) and (b)
4. Neither (a) nor (b)

Explanation: The summation of three sinusoidal waves is equal to AM Waves.

10. The space waves that are seriously affected by the atmospheric conditions are known as:

1. VHF
2. HUF
3. MF
4. UHF