Propagation of radio-TV signals
1. Ground waves have a wavelength
(a) Less than 200 m
(b) Equal to 200 m
(c) more than 200 m
(d) all of these
Ans: ( c)
2. sky wave have a wavelength
(a) Less than 200 m
(b) Equal to 200 m
(c) more than 200 m
(d) all of these
Ans: ( b)
3. Television signals reach us only through the ground waves. The range R related with the transmitter height h is in proportion to
(a) h
(b) h1/2
(c) h-1/2
(d) h-1
Ans: ( b)
4. transmission via sky waves is impossible for the frequencies
(a) less than 40 MHz
(b) equal to 40 MHz
(c) More than 40 MHz
(d) All of these
Ans: ( c)
5. The small ozone layer on the top of the atmosphere is crucial for human survival because it
(a) Has ions
(b) Reflects radio signals
(c) Absorbs UV rays
(d) Reflects IR rays
Ans: ( c)
6. Some scientists have predicted that a global nuclear war on the earth would be followed by a severe.
(a) Rain
(b) Winter
(c) Summer
(d) Radiations hilly rays
Ans: (b)
7. The frequency from 3 to 30 MHz is known as:
(a) Audio band
(b) Medium freq. band
(c) High freq. band
(d) Very high freq. band
Ans: ( c)
8. Which one are better carriers of signals?
(a) Radio waves
(b) Light waves
(c) Micro waves
(d) Ultrasonic waves.
Ans: ( c)
9. It is necessary to use satellites for long distance TV transmission because:
(a) TV signal has short wavelength
(b) TV signal has long wavelength
(c) TV signal has light signals
(d) TV signal are not reflected by ionosphere.
Ans: ( d)
10. Radio waves of constant amplitude can be generated with:
(a) Rectifier
(b) Filter
(c) F.E.T.
(d) Oscillator.
Ans: (d)