11th class (Fsc) Physics unit 9 MCQs
chapter 9 MCQs 11th Class Physics
Physical Optics:
1. Angle between ray of light and wave front is:
a. 90o
b. 0o
c. 120o
d. 60o
2. Intensity of light depends on:
a. Velocity
b. Wavelength
c. Frequency
d. Amplitude
3. A ray of light shows the direction of propagation of light. It is a line which is:
a. Opposite to wave front
b. Normal to the wave front
c. Equal to wave front
d. Parallel to wave front
4. A bat finding its correct location by sending:
a. Infrasonic waves
b. Matter waves
c. Electromagnetic waves
d. Ultrasonic waves
5. When light enters glass, it suffers a change in:
a. Velocity
b. Frequency
c. Both velocity and wavelength
d. Wavelength
6. Light entering from air to glass does not give change in its:
a. Velocity
b. Frequency
c. Direction
d. Wavelength
7. Longitudinal waves cannot be:
a. Diffracted
b. Reflected
c. Polarized
d. Refracted
8. The locus of all points in the same phase of Vibration is called:
a. Diffraction
b. Wave front
c. Polarization
d. Interference
9. Huygen’s principle is used to:
a. Find the speed of light
b. Explain polarization
c. Find the index of refraction
d. Locate the wave from
10. According to Huygen’s Principle, each point on a wave front acts as a source of:
a. New wave front
b. Secondary wavelet
c. Sound
d. Primary wavelet
11. An oil film on water surface shows color due to:
a. Polarization
b. Diffraction
c. Dispersion
d. Interference
12. Soap film in sunlight appears colored due to:
a. Scattering of light
b. Dispersion of light
c. Interference of light
d. Diffraction of light
13. In young’s double slit experiment, the position of dark fringes is given by:
a. Ym = (m + 1/2) λL/d
b. Ym = mλL/d
c. Ym = (m + 1/2) λd/L
d. Ym = mλd/L
14. The distance between two adjacent bright or dark fringes is:
a. λL/d
b. d/λL
c. λ/dL
d. 2λd/L
15. In Young’s double slit experiment, the position for bright fringe is:
a. Ym = mλL/d
b. Ym = mλd/L
c. Ym = mLd/λ
d. Ym = mλ/Ld
16. Fringe spacing is equal to:
a. L/λd
b. d/λL
c. mλL/d
d. λL/d
17. Sodium chloride in a flame gives:
a. White light
b. Green light
c. Yellow light
d. Blue light
18. The fringe spacing increases if we use:
a. Green light
b. Red light
c. yellow light
d. blue light
19. Fringe spacing in Young’s double slit experiment increases due to increase in:
a. Order of fringe
b. Slit separation
c. Frequency of source
d. Wavelength
20. The distance between two adjacent dark fringes is given as:
a. ΔY = (m+1/2)L/d
b. ΔY λL/d
c. ΔY = λd/L
d. ΔY mλL/d
21. The center of Newton’s rings is dark due to:
a. Constructive interference
b. Destructive interference
c. Polarization
d. Diffraction
22. The Fringe spacing in a double slit experiment can be increased by decreasing:
a. Slit separation
b. Wavelength of light
c. Distance between the slits and the screen
d. Width of slits
23. Fringe spacing ins inversely proportional to:
a. Distance between the slits and the screen
b. Wavelength
c. Frequency of light
d. Slit separation
24. In Young’s experiment with one source and two slits, one of the slits is covered with black paper, then:
a. The fringes will be broader
b. The fringes will be darker
c. None fringes will be obtained and the screen will have uniform illumination
d. The fringes will be narrower
25. If red light is used as compared to blue light, then fringe spacing:
a. Remains same
b. Increases
c. Becomes zero
d. Decreases