Wave theory of Light, Interference & Diffraction(Test 2)

This is the 2nd in a series of tests to be put on this blog.
This test consists of MCQ questions from Circular Motion and Gravitation. There are 15 questions in all.
The people taking this test should mark the correct choice in the Response sheet
All entries submited before 9th Oct,12.00pm will be graded.

1.The reciprocal of wavelength is called_____
a) frequency
b) wave velocity
c) amplitude
d) wave number

2.The distance between two consecutive bright fringes increases as____
a) the wavelength increases
b) the frequency increases
c) the wavelength decreases
d) the separation of two sources increases

3.Light is incident upon a rectangular glass block at the polarizing angle. The fraction of light reflected as plane polarized light will be about______
a) zero
b) 10%
c) 50%
d) 100%

4.Shadows are never completely dark because of______
a) interference
b) diffraction
c) polarization
d) reflection

5.The rectilinear propagation of light in a medium is due to its______
a) high velocity
b) large wavelength
c) high frequency
d) source

6.A diffraction pattern is obtained using a beam of red light. What happens if the red light is replaced by blue light?
a) nochange
b) Diffraction bands become narrower and crowded together
c) Band become broader and farther apart
d) Bands disappear altogether

7. The numerical aperture for a human eye is of the order of _____
a)1
b)0.1
c)0.01
d)0.001

8.A ray of light travelling in a transparent medium of refractive index μ, falls on a surface separating the medium from air at an angle of incidence of 45⁰. For which value of μ the ray can undergo total internal reflection?
a) μ=1.33
b) μ=1.40
c) μ= 1.50
d) μ = 1.25


9.Two coherent monochromatic light beams of intensities I and 4I are superimposed. The maximum and minimum intensities in the resulting beam are_____
a) 5I, I
b) 5I, 3I
c) 9I, I
d) 9I, 3I

10. Critical angle for a certain medium is sin^-1(0.6).The polarizing angle of that medium is _____
a) tan^-1(1.5)
b) sin^-1(0.8)
c) tan^-1(1.6667)
d) tan^-1(0.6667)

11.In Young’s double slit experiment; the length of band is 1mm. The fringe width is 0.021mm. The number of fringes is
a) 45
b) 46
c) 47
d) 48



12.Two slits separated by a distance of 1mm are illuminated with red light of wavelength 6.5 x 10^-7m. The interference fringes are observed on the screen placed 1m from the slits. The distance between the third dark fringe and the fifth bright fringe is equal to _______
a) 0.65mm
b) 1.63mm
c) 3.25mm
d) 4.88mm


13.The wavelength of the light used in Young's double slit experiment is λ. The intensity at a point on the screen where the path difference λ/6 is I. If I₀ denotes the maximum intensity,then the ratio of I and I₀ is ______.
a) 0.866
b) 0.5
c) 0.707
d) 0.75

14. A boat has green light of wavelength λ= 500nm on the mast.What wavelength would be measured and what colour would be observed for this light as seen by a diver submerged in water by the side of the boat? Given n_w=4/3
a) Green of wavelength 376nm
b) Red of wavelength 665nm
c) Green of wavelength 500nm
d) Blue of wavelength 376nm

15. Two waves coming from coherent sources, having different intensities interfere.Their ratio of maximum intensity to the minimum intensity is 25:1. The intensities of the sources are in the ratio ___________
a) 25:1
b) 25:16
c) 9:4
d) 5:1