1. A beam of light of \(\lambda\) = 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between first dark frings on either side of the central bright fringe is

(1).1.2 cm

(2). 1.2 mm

(3). 2.4 cm

(4). 2.4 mm

2. In the Young's double-slit experiment, the intensity of light at a point on the screen (where the path difference is \(\lambda\) is K, (\(\lambda being the wavelength of light used). The intensity at a point where the path difference is \(\frac{\lambda}{4}\), will be

(1).K

(2). K/4

(3). K/2

(4). zero

3. An unpolarised light beam strikes a glass surface at Brewster’s angle. Then

(1).both the reflected and refracted light will be completely polarised

(2). the reflected light will be completely polarised but the refracted light will be partially polarised (

(3). the reflected light will be partially polarised

(4). the refracted light will be completely polarised

4. If the monochromatic source in Young's double slit experiment is replaced by white light, then

(1).there will be a central bright white fringe surrounded by a few coloured fringes.

(2). all bright fringes will be of equal width.

(3). interference pattern will disappear.

(4). there will be a central dark fringe surrounded by a few coloured fringes.

5. In a Young’s double slit experiment, a student observes 8 fringes in a certain segment of screen when a monochromatic light of 600 nm wavelength is used. If the wavelength of light is changed to 400 nm, then the number of fringes he would observe in the same-region of the screen is :

(1).6

(2). 8

(3). 9

(4). 12

6. Assume that light of wavelength 600 nm is coming from a star. The limit of resolution of telescope whose objective has a diameter of 2 m is

(1).\(1.83 \times 10^{-7}\) rad

(2). \(7.32 \times 10^{-7}\) rad

(3). \(6.00 \times 10^{-7}\) rad

(4). \(3.66 \times 10^{-7}\) rad

7. 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

8. The Brewsters angle \(i_b\) 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). \(0^\circ\, <\, i_b\, <\, 30^\circ\)

9. For a parallel beam of monochromatic light of wavelength ‘λ’, diffraction is produced by a single slit whose width ‘a’ is of the order of the wavelength of the light. If ‘D’ is the distance of the screen from the slit, the width of the central maxima will be:

(1).\(\displaystyle \frac{2D\lambda}{a}\)

(2). \(\displaystyle \frac{D\lambda}{a}\)

(3). \(\displaystyle \frac{Da}{\lambda}\)

(4). \(\displaystyle \frac{2Da}{\lambda}\)

10. In a double slit experiment, the two slits are 1 mm apart and the screen is placed 1 m away. A monochromatic light of wavelength 500 nm is used. What will be the width of each slit for obtaining ten maxima of double slit within the central maxima of single slit pattern?

(1).0.2 mm

(2). 0.1 mm

(3). 0.5 mm

(4). 0.02 mm

11. The intensity of transmitted light when a polaroid sheet, placed between two crossed polaroids at \(22.5^\circ\) from the polarization axis of one of the polaroid, is (\(\text{l}_0\) is the intensity of polarised light after passing through the first polaroid):

(1).\(\displaystyle \frac{\text{I}_0}{16}\)

(2). \(\displaystyle \frac{\text{I}_0}{2}\)

(3). \(\displaystyle \frac{\text{I}_0}{4}\)

(4). \(\displaystyle \frac{\text{I}_0}{8}\)

12. An unpolarized light beam travelling in air is incident on a medium of refractive index 1.73 at Brewster's angle. Then-

(1).transmitted light is completely polarized with angle of refraction close to \(30^\circ\)

(2). reflected light is completely polarized and the angle of reflection is close to \(60^\circ\)

(3). reflected light is partially polarized and the angle of reflection is close to \(30^\circ\)

(4). both reflected and transmitted light are perfectly polarized with angles of reflection and refraction close to \(60^\circ\) and \(30^\circ\), respectively.