In young's experiment, the wavelength of red light is cm and that of blue light cm. The value of n for which (n+1)th blue bright band coincides with the nth red band is:
1. 4
2. 3
3. 2
4. 1
In Young's double-slit experiment, if the separation between coherent sources is halved and the distance of the screen from the coherent sources is doubled, then the fringe width becomes:
1. | half | 2. | four times |
3. | one-fourth | 4. | double |
The Brewster's angle for an interface should be:
1. \(30^{\circ}<i_b<45^{\circ}\)
2. \(45^{\circ}<i_b<90^{\circ}\)
3. \(i_b=90^{\circ}\)
4. \(0^{\circ}<i_b<30^{\circ}\)
In Young’s double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Determine the wavelength of light used in the experiment.
1. 600 nm
2. 500 nm
3. 400 nm
4. 200 nm
In Young’s double-slit experiment using monochromatic light of wavelength \(\lambda,\) the intensity of light at a point on the screen where path difference \(\lambda\) is \(K\) units. What is the intensity of the light at a point where path difference is \(\lambda/3\)?
1. \(\frac K3\)
2. \(\frac K4\)
3. \(\frac K2\)
4. \(K\)
In a double-slit experiment the angular width of a fringe is found to be \(0.2^\circ\) on a screen placed \(1\) m away. The wavelength of light used is \(600\) nm. What will be the angular width of the fringe if the entire experimental apparatus is immersed in water?
(Take the refractive index of water to be \(4/3\)).
1. \(0.33^\circ\)
2. \(0.20^\circ\)
3. \(0.15^\circ\)
4. \(0.10^\circ\)
What is the Brewster angle for air to glass transition? (Refractive index of glass = 1.5.)
1.
2.
3.
4.
What is the distance for which ray optics is a good approximation for an aperture of 4 mm and wavelength 400 nm?
1. 40 m
2. 30 m
3. 20 m
4. 50 m
The resolving power of an electron microscope is \(R,\) when the accelerating potential is \(V.\) If the accelerating potential is increased by \(3V,\) then it's new resolving power is:
1. \(3R\)
2. \(2R\)
3. \(4R\)
4. \(R\)
When the light diverges from a point source, the shape of the wavefront is:
1. Parabolic.
2. Plane.
3. Spherical.
4. Elliptical.