Worksheet

1.

In amplitude modulation, the modulation index $m$, is kept less than or equal to 1 because

a. $m > 1$, will result in interference between carrier frequency and message frequency, resulting into distortion. b. $m > 1$ will result in overlapping of both side bands resulting into loss of information. c. $m > 1$ will result in change in phase between carrier signal and message signal. d. $m > 1$ indicates amplitude of message signal greater than amplitude of carrier signal resulting into distortion.

2.

An audio signal of 15kHz frequency cannot be transmitted over long distances without modulation because

a. the size of the required antenna would be at least 5 km which is not convenient. b. the audio signal can not be transmitted through sky waves. c. the size of the required antenna would be at least 20 km, which is not convenient. d. effective power transmitted would be very low, if the size of the antenna is less than 5 km.

3.

An audio signal of 15kHz frequency cannot be transmitted over long distances without modulation because

a. the size of the required antenna would be at least 5 km which is not convenient. b. the audio signal can not be transmitted through sky waves. c. the size of the required antenna would be at least 20 km, which is not convenient. d. effective power transmitted would be very low, if the size of the antenna is less than 5 km.

4.

The frequency response curve (Fig. 15.2) for the filter circuit used for production of AM wave should be

The frequency response curve (Fig. 15.2) for the filter circuit used for production of AM wave should be - Sarthaks eConnect | Largest Online Education Community

a.

(i) followed by (ii).

b.

(ii) followed by (i).

c.

(iii).

d.

(iv).

5.

In amplitude modulation, the modulation index m, is kept less than or equal to 1 because

a. (m > 1), will result in interference between carrier frequency and message frequency, resulting into distortion. b. (m > 1) will result in overlapping of both side bands resulting into loss of information. c. (m > 1) will result in change in phase between carrier signal and message signal. d. (m > 1) indicates amplitude of message signal greater than amplitude of carrier signal resulting into distortion.

6.

The frequency response curve (Fig. 15.2) for the filter circuit used for production of AM wave should be

The frequency response curve figure for the filter class 12 physics CBSE

a.

(i) followed by (ii).

b.

(ii) followed by (i).

c.

(iii).

d.

(iv).

7.

A TV trasmission tower has a height of 240 m. Signals broadcast from this tower will be received by LOS communication at a distance of (assume the radius of earth to be $6.4 \times 10^6$ m)

a. 100 km. b. 24 km. c. 55 km. d. 50 km.

8.

A TV trasmission tower has a height of 240 m. Signals broadcast from this tower will be received by LOS communication at a distance of (assume the radius of earth to be (6.4 \times 10^{6}) m)

a. 100 km. b. 24 km. c. 55 km. d. 50 km.

9.

Audio sine waves of 3 kHz frequency are used to amplitude modulate a carrier signal of 1.5 MHz. Which of the following statements are true?

a. The side band frequencies are 1506 kHz and 1494 kHz. b. The bandwidth required for amplitude modulation is 6kHz. c. The bandwidth required for amplitude modulation is 3 MHz. d. The side band frequencies are 1503 kHz and 1497 kHz.

10.

Audio sine waves of 3 kHz frequency are used to amplitude modulate a carrier signal of 1.5 MHz. Which of the following statements are true?

a. The side band frequencies are 1506 kHz and 1494 kHz. b. The bandwidth required for amplitude modulation is 6kHz. c. The bandwidth required for amplitude modulation is 3 MHz. d. The side band frequencies are 1503 kHz and 1497 kHz.