1. Who undertook the first space walk and in which year ?
(A) Leonov, 1965
(B) Neil Armstrong, 1969
(C) Rakesh Sharma, 1998
(D) None of these
| Answer ⇒ A |
2. The term used “to collect the information about an object and a place without physical contact” is called :
(A) modulation
(B) communication
(C) amplification
(D) remote sensing
| Answer ⇒ D |
3. The velocity of electromagnetic wave is :
(A) 3 x 105 ms-1
(B) 3 x 106 ms-1
(C) 3 x 108 ms-1
(D) 3 x 1010 ms-1
| Answer ⇒ C |
4. The audio frequencies range from :
(A) 20 Hz to 20,000 kHz
(B) 20 Hz to 20 kHz
(C) 20 kHz to 20,000 kHz
(D) None of these
| Answer ⇒ D |
5. The wavelength of a wave of frequency 10 kHz is :
(A) 30 m
(B) 300 m
(C) 30 km
(D) 300 km
| Answer ⇒ C |
6. The area served by an antenna of height 100 m is :
(A) 109 m2
(B) 4 x 109 m2
(C) 6 x 109 m2
(D) 8 x 1010 m2
| Answer ⇒ B |
7. Which of the following is not transducer ?
(A) Loudspeaker
(B) Amplifier
(C) Microphone
(D) All
| Answer ⇒ B |
8. The space waves which are affected seriously by atmospheric conditions are :
(A) MF
(B) HUF
(C) VHF
(D) UHF
| Answer ⇒ D |
9. An antenna is :
(A) Inductive
(B) Capacitive
(C) Resistive
(D) A transformer
| Answer ⇒ A |
10. Broadcasting antenna are generally :
(A) Ommi directional type
(B) Vertical type
(C) Horizontal type
(D) None
| Answer ⇒ B |
11. The modulation index in amplitude modulation is :
(A) Always zero
(B) Between 0 and 1
(C) Between 1 and ∞
(D) None of these
| Answer ⇒ C |
12. The output of a digital computer is an example of :
(A) digital signal
(B) analog signal
(C) both (A) and (B)
(D) neither (A) nor (B)
| Answer ⇒ A |
13. Name the man who was first to place his foot on the moon and in which year :
(A) Neil Armstrong, 1969
(B) James Van Allen, 1971
(C) Leonov, 1965
(D) None of these
| Answer ⇒ A |
14. A microphone converts :
(A) sound signals into electrical signals
(B) electrical signals into sound signals
(C) both (A) and (B)
(D) Neither (A) nor (B)
| Answer ⇒ A |
15. A loudspeaker converts :
(A) electrical signals into sound signals
(B) sound signals into electrical signals
(C) both (A) and (B)
(D) neither (A) nor (B)
| Answer ⇒ A |
16. The sound produced by a tuning fork is a sort of:
(A) analog signal
(B) digital signal
(C) both (A) and (B)
(D) neither (A) nor (B)
| Answer ⇒ A |
17. The length of a half wave dipole at 30 mega hertz is :
(A) 5 m
(B) 10 m
(C) 25 m
(D) 80 m
| Answer ⇒ A |
18. In space communication, the sound waves can be sent from one place to another :
(A) through space
(B) through wires
(C) by superimposing it on undamped electro magnetic waves
(D) by superimposing it on damped electro magnetic waves
| Answer ⇒ C |
19. The output of a digital computer is an example of:
(A) digital signal
(B) analog signal
(C) both (A) and (B) above
(D) neither (A) nor (B)
| Answer ⇒ A |
20. Which is more advantageous ?
(A) analog data communication
(B) digital data communication
(C) both (A) and (B) are equally good
(D) depends on the situation
| Answer ⇒ B |
21. A byte is a string of n bits. Then n equals :
(A) 8
(B) 6
(C) 4
(D) 2
| Answer ⇒ A |
22. When the modulation percentage is 75, an AM transmitter produces 10 kW. How much of this is carrier power ?
(A) 10 kW
(B) 12.30 kW
(C) 7.5 kW
(D) 7.81 kW
| Answer ⇒ D |
23. The range of frequencies allotted for commercial FM radio broadcast is :
(A) 88 to 108 MHz
(B) 88 to 108 kHz
(C) 8 to 889 MHz
(D) None of these
| Answer ⇒ A |
24. The range of frequencies allotted for commercial VHF TV broadcast is :
(A) 76-88 MHz
(B) 54-72 MHz
(C) 174-216 MHz
(D) None of these
| Answer ⇒ B |
25. The range of frequencies allotted for commercial UHF TV broadcast is :
(A) 76-88 MHz
(B) 54-72 MHz
(C) 174-216 MHz
(D) None of these
| Answer ⇒ C |
26. Basically a communication system is a:
(A) transmitter
(B) receiver
(C) messenger
(D) None of these
| Answer ⇒ C |
Class 12th physics objective question in English
