PHYSICS 2020 FINAL EXAM QUESTIONS
WITH VERIFIED SOLUTIONS NEW
MODIFIED EXAM
A train A blows a whistle at 600 Hz. A passenger in a train B hears a frequency
of 620 Hz. From this, it *follows* that
(i) A is stationary and B is moving towards A
(ii) the distance between A and B is decreasing with time
(iii) B is stationary and A is moving towards B
(iv) the passenger in B will see train A coming closer --CORRECT ANSWER--
*(ii) the distance between A and B is decreasing with time*
*(iv) the passenger in B will see train A coming closer*
Common waves (except water) are either transverse or longitudinal.
(i) sound traveling through air is a transverse wave
(ii) the up and down oscillations in horizontal rope travel as a transverse wave
(iii) sound traveling through air is a longitudinal wave
(iv) vibrations (compressions and rarefactions) travel through a spring as a
transverse wave --CORRECT ANSWER--*(ii) the up and down oscillations in
horizontal rope travel as a transverse wave*
*(iii) sound traveling through air is a longitudinal wave*
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,The wavelength of a wave is 3.0 m and its frequency is 4.0 Hz (v = fλ) --
CORRECT ANSWER--*(i) the speed of the wave is 12 m/s*
*(ii) the distance between two nearest crests of the wave is 3.0m*
The human ear can hear between 20 Hz and 20000 Hz. So
(i) 15 Hz is infrasonic
(ii) 25000 Hz is ultrasonic
(iii) 40000 Hz is supersonic
(iv) 10 Hz is subsonic --CORRECT ANSWER--*(i) 15 Hz is infrasonic*
*(ii) 25000 Hz is ultrasonic*
The following quantities are measured in watts (W)
(i) power
(ii) sound intensity
(iii) sound intensity level
(iv) energy spent or produced per unit time --CORRECT ANSWER--*(i)
power*
*(iv) energy spent or produced per unit time*
The symbol β is used for
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, (i) sound intensity
(ii) sound intensity level
(iii) decibel level
(iv) power --CORRECT ANSWER--*(ii) sound intensity level*
*(iii) decibel level*
Log(4000)^10 is equal to
(i) 4 * 10^3
(ii) 3 + log 4
(iii) 3.602
(iv) log 4 * log 1000 --CORRECT ANSWER--*(ii) 3 + log 4*
*(iii) 3.602*
A simple pendulum consists of a small bob suspended by a light string. --
CORRECT ANSWER--*(ii) the oscillation is Simple Harmonic only for small
angular displacements*
*(iii) the period of the pendulum depends on the acceleration due to gravity g*
One speaker is placed at a distance of x meters behind another. The two
speakers are sounding the same frequency in phase. The sound is observed
along the line of the speakers. --CORRECT ANSWER--*(i) there will be
constructive interference if x is equal to a whole multiple of wavelengths*
*(iii) there will be destructive interference if x is equal to half a wavelength*
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WITH VERIFIED SOLUTIONS NEW
MODIFIED EXAM
A train A blows a whistle at 600 Hz. A passenger in a train B hears a frequency
of 620 Hz. From this, it *follows* that
(i) A is stationary and B is moving towards A
(ii) the distance between A and B is decreasing with time
(iii) B is stationary and A is moving towards B
(iv) the passenger in B will see train A coming closer --CORRECT ANSWER--
*(ii) the distance between A and B is decreasing with time*
*(iv) the passenger in B will see train A coming closer*
Common waves (except water) are either transverse or longitudinal.
(i) sound traveling through air is a transverse wave
(ii) the up and down oscillations in horizontal rope travel as a transverse wave
(iii) sound traveling through air is a longitudinal wave
(iv) vibrations (compressions and rarefactions) travel through a spring as a
transverse wave --CORRECT ANSWER--*(ii) the up and down oscillations in
horizontal rope travel as a transverse wave*
*(iii) sound traveling through air is a longitudinal wave*
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,The wavelength of a wave is 3.0 m and its frequency is 4.0 Hz (v = fλ) --
CORRECT ANSWER--*(i) the speed of the wave is 12 m/s*
*(ii) the distance between two nearest crests of the wave is 3.0m*
The human ear can hear between 20 Hz and 20000 Hz. So
(i) 15 Hz is infrasonic
(ii) 25000 Hz is ultrasonic
(iii) 40000 Hz is supersonic
(iv) 10 Hz is subsonic --CORRECT ANSWER--*(i) 15 Hz is infrasonic*
*(ii) 25000 Hz is ultrasonic*
The following quantities are measured in watts (W)
(i) power
(ii) sound intensity
(iii) sound intensity level
(iv) energy spent or produced per unit time --CORRECT ANSWER--*(i)
power*
*(iv) energy spent or produced per unit time*
The symbol β is used for
Page | 2
, (i) sound intensity
(ii) sound intensity level
(iii) decibel level
(iv) power --CORRECT ANSWER--*(ii) sound intensity level*
*(iii) decibel level*
Log(4000)^10 is equal to
(i) 4 * 10^3
(ii) 3 + log 4
(iii) 3.602
(iv) log 4 * log 1000 --CORRECT ANSWER--*(ii) 3 + log 4*
*(iii) 3.602*
A simple pendulum consists of a small bob suspended by a light string. --
CORRECT ANSWER--*(ii) the oscillation is Simple Harmonic only for small
angular displacements*
*(iii) the period of the pendulum depends on the acceleration due to gravity g*
One speaker is placed at a distance of x meters behind another. The two
speakers are sounding the same frequency in phase. The sound is observed
along the line of the speakers. --CORRECT ANSWER--*(i) there will be
constructive interference if x is equal to a whole multiple of wavelengths*
*(iii) there will be destructive interference if x is equal to half a wavelength*
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