Question 1. The optimum sound level for human beings is _______.
(A) 100 dB
(B) 120 dB
(C) 60 dB
(D) 90 dB
Question 2. A worker was working on the rail track. A boy at a distance holds his ear near the rail track. This boy was able to hear sound of the blow of workman twice. It is because of _____.
(A) His ears are at different distance from the source
(B) Part of the sound wave is reflected between the rail tracks
(C) The speed of sound is greater in air than in steel
(D) The speed of sound is greater in steel than in air
Question 3. When the same note is played on a sitar and a flute, the sound produced can be distinguished from each other because of the difference in _______.
(A) loudness only
(B) quality only
(C) pitch and loudness
(D) pitch, loudness and quality
Question 4. Which of the following has the longest wavelength?
(A) Radio waves
(B) Visible light
(C) X-rays
(D) Infrared
Question 5. Which one of the following does a TV remote control unit use to operate a TV set?
(A) Radio waves
(B) Micro waves
(C) Sound waves
(D) Light waves
Question 6. Which type of electromagnetic radiation is used in the remote control of a television?
(A) Infra-red
(B) Visible
(C) Ultraviolet
(D)None of these
Question 7. The Doppler’s effect is applicable for______.
(A) Light waves
(B) Space waves
(C) Sound waves
(D) Both (A) and (C)
Question 8. When T.V. is switched on ______.
(A) It depends on the T.V. brand
(B) Video starts immediately but audio is heard later because sound travels at a lesser speed than light
(C) Audio is heard immediately but video starts later because video needs some warm up time
(D) Audio and video both start simultaneously
Question 9. In television broadcast, the picture signals are transmitted by _________.
(A) Angle modulation
(B) Phase modulation
(C) Frequency modulation
(D) Amplitude modulation
Question 10. The technique used to transmit audio signals in television broadcast is ________.
(A) Time dimension multiplication
(B) Frequency modulation
(C) Pulse code modulation
(D) Amplitude modulation
Question 11. A radio station broadcast at 30 metre band. The frequency of the carrier wave transmitted by this station is ______.
(A) 100 MHz
(B) 10 MHz
(C) 100 kHz
(D) 10 kHz
Question 12. Put in ascending order the speed of sound in the mediums.
- Water
- Steel
- Nitrogen
(A) 2, 1, 3
(B) 1, 3, 2
(C) 3, 1, 2
(D) 3, 2, 1
Question 13. Consider the following statements.
- A flute of smaller length produces waves of lower frequency.
- Sound travels in rocks in the form of longitudinal elastic waves only.
Which of the statements given above is/are correct?
(A) Neither 1 nor 2
(B) Both 1 and 2
(C) Only 2
(D) Only 1
Question 14. Consider the following statements about ultrasonic waves.
- They can destroy insects.
- They can clean clothes by removing dust.
- They can be used to treat diseases.
- They can control automatic doors. Of the above statements.
(A) 1 and 2 are correct
(B) 1, 2 and 3 are correct
(C) 3 and 4 are correct
(D) All are correct
Question 15. Consider the following statements.
- The heart vibrates at infrasonic.
- The speed of sound is more in gas than in liquid and solid.
- Mach number is used to describe the speed of sound.
- Ultrasonic sound has frequency more than 20,000 Hz. Of these statements.
(A) 1, 2 and 4 are correct
(B) 1, 3 and 4 are correct
(C) 2, 3 and 4 are correct
(D) 1, 2 and 3 are correct
Question 16.
- Assertion (A): A jet aircraft moving at mach number equal to 1 travels faster at an altitude of 15 km than while moving at mach number equal to 1 near the sea level.
- Reason (R): The velocity of sound depends on the temperature of the surrounding medium.
(A) (A) is false, but (R) is true
(B) (A) is true, but (R) is false
(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
(D) Both (A) and (R) are true and (R) is the correct explanation of (A)
Question 17.
- Assertion (A): Reverberation mainly feels in large churches and in other large buildings.
- Reason (R): The walls, roof and ground may cause multiple sound reflections.
(A) (A) is false, but (R) is true
(B) (A) is true, but (R) is false
(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
(D) Both (A) and (R) are true and (R) is the correct explanation of (A)
Question 18. Consider the following statements.
- A widely used musical scale called diatonic scale has seven frequencies.
- The frequency of the tone Sa is 256 Hz and that of Ni is 512 Hz.
Which of the statements given above is/are correct?
(A) Both 1 and 2
(B) Only 2
(C) Only 1
(D) Neither 1 nor 2
Question 19.
- Assertion (A): Radio waves bend in a magnetic field.
- Reason (R): Radio waves are electromagnetic in nature.
(A) (A) is false, but (R) is true
(B) (A) is true, but (R) is false
(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
(D) Both (A) and (R) are true and (R) is the correct explanation of (A)