bcafamilyOptics
61. Light of wavelength 550 nm falls normally on a slit of width 22 x 10-7m, the angular position of second minima from central maxima will be [2075]
14.5°
30°
42°
62°
62. Two lens of power 5D and -7.5D are placed in contact.The equivalent focal length of combination will be[2075]
-40cm
+40cm
-25cm
+25cm
63. The length of the microscope is 14 cm and magnifying power is 25 for relaxed eye the focal length of the eyepiece is 5 cm then a distance of object from objective is [2075]
2.4cm
2.1cm
1.5cm
1.8cm
63. The Illuminance at distance of 2 m from a 100 candle lamp is [2074]
10 lux
15 lux
25 lux
100 lux
64. When light beam is incident on a prism, it causes [2074]
lateral shift
dispersion only
deviation only
dispersion and deviation
65. If critical angle for a material placed in air is 30° the refractive index will be [2074]
2
0.5
1.5
2.5
67. On heating a liquid, the refractive index generally [2074]
does not change
decrease
increase
may increase or decrease depending upon the rate of heating
61. The field of view is maximum for. [2073]
plane mirror
concave mirror
convex spectrum
Cylindrical mirror
62. The sky seen from earth appears blue because of [2073]
scattering of lights
dispersion of lights
reflection
polarization
63. A person cannot see objects clearly beyond 50 cm. The power of the lens to correct the vision is [2073]
+5D
-5 D
-0.5 D
-2 D
61. A ray of light in air enters a glass slab. Its [2072]
wave length decrease
wave length increases
speed increases
frequency decreases
62. By using white light in double slit interference experiment the central fringe is white. What color of fringe can be seen nearest to the central fringe? [2072]
blue
green
red
violet
63. A convex lens is immersed in water. Compared to its power in air, the power in water will [2072]
increase for red and decrease for blue
decrease for all colors
be same for all colors
increase for all colors
63. The image of an object placed at the focus of conves mirror is ar a distance [2071]
∞
f
2f
f/2
64. If sky is seen from moon's surface, it will appear [2071]
black
Blue
White
Red
65. A double convex air bubble in a glass sheet would behave as a [2071]
Convergent lengs
Concave mirror
Divergent Lens
Plane Mirror
66. When two prism are combined it gives [2071]
Reflection only
lateral shift
Dispersion and deviation both
Dispersion or deviation
59. The image of an object placed at the focus of a concave mirror is at
f
Infinity
2f
f/2
61. The refractive index of air with respect to glass is 2/3. The refractive index of diamond with respect to air is 12/5. Then the refractive index of glass with respect to diamond will be. [2070]
5/8
8/9
5/18
18/5
62. The focal length of a double conves lens for which radius of curvature of each surface is R will be ....( µ = 1.5) [2070]
R/2
R
2R
4R
63. Light of wave length 7200 Å in air has wave length in glass equal to ......... (given Refractive index of glass with respect to air = 1.5) [2070]
7200 Å
4800 Å
1080 Å
10800 Å
58. A myopic eye cannot see object beyond 1.5m. What power of lens will be required to correct this defect of vision? [2069]
1.5 D
0.66 D
-1.5 D
-0.66 D
59. The critical angel of glass water interface is [2069]
sin-1(8/9)
sin-1(4/5)
sin-1(3/4)
sin-1(2/3)
60. A Diffraction granting has 5000 lines per cm. The maximum order visible with the radiation of wavelength 600 nm in diffraction experiment. [2069]
2
3
4
0
61. Light travels through a glass of thickness t and refractive index n. If C is the velocity of light in vacuum, the time taken by light to travel this thickness is[2069]
t/ne
cnt
nt/c
tc/n
