11th class (Fsc) Physics unit 8 MCQs
chapter 8 MCQs 11th Class Physics
Waves:
1. When the amplitude of a wave is increases to double is energy?
a. Increases 4 times
b. Remain the same
c. Decreases by half
d. Increase by two times
2. The distance covered by wave in 1 sec is:
a. Frequency
b. Wavelength
c. Wave speed
d. Wave number
3. Half wavelength corresponds to:
a. 180o
b. 0o
c. 360o
d. 90o
4. The louder the sound, the greater will be its:
a. Amplitude
b. Speed
c. Wavelength
d. Frequency
5. The error in speed of sound calculated by Newton at STP is about:
a. 16%
b. 6%
c. 26%
d. 10%
6. The speed of sound in air is 340 m /s. if the pressure of air is doubled then the speed becomes:
a. Four times
b. Double
c. Remains same
d. Half
7. Constructive interference of two coherent beams is obtained if path difference is:
a. n(3λ)/4
b. nλ/2
c. nλ
d. nλ/4
8. When two identical waves superimposed, which can change?
a. Velocity
b. Wavelength
c. Amplitude
d. Frequency
9. Two waves having same frequency and travelling in the same direction superimpose each other and corresponding phenomenon is called:
a. Doppler effect
b. Interference
c. Stationary waves
d. Beats
10. When two identical travelling waves superimposed, velocity of resultant wave:
a. Remain same
b. Decreases
c. Becomes zero
d. Increases
11. Diffraction is a special type of:
a. Interference
b. Reflection
c. Refraction
d. Polarization
12. Two tuning forks of frequencies 260 Hz and 256 Hz are sounded together, the number of beats per second is:
a. 2
b. 4
c. 516
d. 258
13. On loading the prong of a tuning fork with wax, the frequency of sound:
a. Remain same
b. Increases
c. First increases than decreases
d. Decreases
14. Two tuning forks of frequencies 240 Hz and 245 Hz are sounded together, the number of beats per seconds is:
a. 3
b. zero
c. 2
d. 4
15. The phase between two points on the same wave front is:
a. 𝜋/2
b. 2𝜋
c. 0
d. 𝜋
16. A stretched string 4m long and it has 4 loops of stationary waves, then the wavelength is:
a. 3 m
b. 1 m
c. 4 m
d. 2 m
17. A spring of length l fixed at both ends is vibrating in two segments, the wavelength of wave is:
a. 2L
b. L/2
c. 3L
d. L
18. Stationary waves are generated on a string of length If tension is increased, frequency of vibration will:
a. Half
b. Decrease
c. Increase
d. Unchanged
19. The state of human blood flow can be found by using:
a. Phenomenon of beats
b. Newton’s formula of speed of sound
c. Doppler’s effect of sound
d. Interference of sound
20. A stationary wave is established in a string which vibrates n four segments at a frequency of 120 Hz. Its fundamental frequency is:
a. 60 Hz
b. 15 Hz
c. 480 Hz
d. 30 Hz
21. When sound waves enter in different medium, the quantity that remains unchanged is:
a. Frequency
b. Intensity
c. Wavelength
d. Speed
22. Two waves of same frequency and moving in the same direction produces:
a. Beats
b. Interference
c. Stationary wave
d. Diffraction
23. The wavelength of fundamental node of vibration of an open-end pipe is:
a. i
b. 4i
c. 1/4i
d. 2i
24. Wavelength of a wave for closed pipe having length ‘I’ in the fundamental mode is:
a. 4i
b. 2i
c. i
d. i/2
25. The pitch of sound depends upon:
a. Wavelength of sound
b. Intensity of sound
c. Frequency of sound
d. Loudness of sound