Wave Optics · Question 26

A linear aperture whose width is 0.02 cm is placed immediately in front of a lens of focal length 60 cm. The aperture is illuminated normally by a parallel beam of wavelength 5 10-5 cm. The distance of the first dark band of the diffraction pattern from the centre of the screen is

1. 0.10 cm
2. 0.25 cm
3. 0.20 cm
4. 0.15 cm

At the first minimum adjacent to the central maximum of a single-slit diffraction pattern, the phase difference between the Huygen's wavelet from the edge of the slit and the wavelet from the midpoint of the slit is

1. radian
2. 8 radian
3. 4 radian
4. 2 radian

Two slits in Young's experiment have widths in the ratio 1 : 25. The ratio of intensity at the maxima and minima in the interference pattern, I I is

1. 49121
2. 49
3. 94
4. 12149

For a parallel beam of monochromatic light of wavelength ' ', 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. Da
2. 2Da
3. 2D a
4. D a

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. 0.5 mm
2. 0.02 mm
3. 0.2 mm
4. 0.1 mm

A beam of light of = 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 fringes 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

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

1. K
2. K/4
3. K/2
4. zero

In Young's double slit experiment, the slits are 2 mm apart and are illuminated by photons of two wavelengths 1 = 12000 A and 2 = 10000 A. At what minimum distance from the common central bright fringe on the screen 2 m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other ?

1. 4 mm
2. 3 m
3. 8 mm
4. 6 mm

In Young's double slit experiment the distance between the slits and the screen is doubled. The separation between the slits is reduced to half. As a result the fringe width

1. is halved
2. becomes four times
3. remains unchanged
4. is doubled

A parallel beam of light of wavelength is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the second minimum of the diffraction pattern, the phase difference between the rays coming from the two edges of slit is

1. 2
2. 3
3. 4