Physics Chapter 4 Entry test MCQs
76. If a wave travelling at a speed of 130 m/s and has a wavelength of 5m. Then find out the frequency of the wave?
a. 20 Hz
b. 650 Hz
c. 26 Hz
d. 3.8 x 102 Hz
77. A metallic wire of 2m length hooked between two points has tension of 10N. If mass per unit length of wire is 0.004 kg/s then fundamental frequency emitted by wire on vibration is:
a. 48 Hz
b. 12.5 Hz
c. 6.25 Hz
d. 24 Hz
78. A source of sound moves towards a stationary observer with speed one third speed of sound. If the frequency of the sound from the source is 100 Hz, the apparent frequency of the sound heard by the observer is:
a. 100 Hz
b. 60 Hz
c. 150 Hz
d. 200 Hz
79. In a stationary wave the distance between consecutive antinodes is 25 cm. If the wave velocity is 300m s-1 then the frequency of the wave will be:
a. 600 Hz
b. 150 Hz
c. 750 Hz
d. 300 Hz
80. The speed of sound in air at NTP is 300m/s. If the air pressure become 4 times then the speed of the sound will be
a. 600m/s
b. 300m/s
c. 150m/s
d. None
81. Standing waves are produced in 10m long stretched string. If the string vibrates in 5 segments and wave velocity is 20m s-1 Its frequency is:
a. 5 Hz
b. 2 Hz
c. 10 Hz
d. 4 Hz
82. A shock wave is produced due to an earthquake which makes the building move in the direction of the shock wave. Which progressive wave would this be?
a. Transverse wave
b. Longitudinal wave
c. Particle wave
d. Material wave
83. Which one of the following varies when an object execute simple harmonic motion?
a. Force
b. Angular frequency
c. Amplitude
d. Total energy
84. Which one of the following is not a characteristic of stationary wave?
a. Phase is identical between two adjacent nodes
b. Half wavelength is half the distance between the adjacent nodes
c. Energy of the stationary waves travels outwards
d. Amplitude is not the same
85. The wavelength of the electromagnetic wave having frequency of 3 kHz will be?
a. 140 km
b. 80 km
c. 120 km
d. 100 km
86. What will be the expression for the observed frequency, if the source is moving towards the observer?
87. The sound in air is 332 m/s. The speed of sound at 22°C will be:
a. 350m/s
b. 345.2m/s
c. 330 m/s
d. 340 m/s
88. Astronomers calculate speed of distant stars and galaxies using which of the following phenomena?
a. Superposition principle
b. Beats
c. Doppler effect
d. Interference
89. In a ripple tank, 40 waves pass through a certain point in 1 second. If the wavelength of the wave is 5cm. then speed of the wave is:
a. 1.5m s-1
b. 0.5ms-1
c. 2m * s-1
d. 1m s-1
90. In ripple tank 40 waves pass through a certain point in one second. If the wavelength of the waves is 5cm, then find the speed of wave.
a. 200m s-1
b. 2.7m s-1
c. 2m s-1
d. 3m s-1
91. Trough of a wave acts as:
a. Convex mirror
b. Concave lens
c. Plane mirror
d. Convex lens
92. Doppler’s effect shows?
a. Change in frequency due to motion of source only
b. Change in frequency due to relative motion between source and observer
c. Change in frequency due to motion of observer only
d. Change in amplitude due to relative motion between source and observer
93. Distance Between two Consecutive node is
a. Wave length by 4
b. Wave length
c. twice of Wave length
d. Wave length by 2
94. Stationary waves
a. Don’t Move
b. Move forward
c. Move in both direction
d. Move backwards
95. Crest and trough are found in?
a. Progressive wave
b. Transvers wave
c. Longitudinal wave
d. None
96. Ratio of fundamental frequency of Open Organ pipe to closed organ pipe is
a. 1:4
b. 1:2
c. 4:1
d. 2:1
97. A whistler with velocity 33 ms-1 approaches towards a stationary observer with frequency 450Hz what is the apparent frequency heard by the observer:
a. 430
b. 500
c. 450
d. 400
98. Ripple tank is used to study features of
a. Light
b. Particle
c. Solid
d. Wave
99. Waves which deal with fast moving elementary particle
a. Matter waves
b. Transverse Waves
c. Periodic waves
d. Longitudinal waves
100. Infrasonic wave has frequency
a. 20Hz
b. Less than 20Hz
c. Greater than 20 kHz
d. Greater than 20Hz