| 1 |
A beam of light enters air from water.Which of the following characteristics of light will not change in water |
Frequency
Wavelength
Velocity
Amplitude
|
| 2 |
Refractive index of material depends upon |
Nature of material
Wave length
Temperature
All of these
|
| 3 |
Two lenses of power +12 and -2 diopters are placed in contact the power of combination is |
10 diopters
8 diopters
6 diopters
12 diopters
|
| 4 |
If the cover of a red book is observed in monochromatic blue light,It will appear |
White
Red
Black
Blue
|
| 5 |
A tourmaline crystal is being used as an analyzer In one complete rotation of the crystal the number of excitation will be |
0
1
2
4
|
| 6 |
A convex lens is dipped in a liquid whose refractive index is equal to the material of the lens. Then its focal length will become |
Infinite
Zero
Extremely small
Extremely large
|
| 7 |
The ratio of the diameter of two convex lenses is the ratio of their focal lengths |
Greater than
Less than
Equal to
None
|
| 8 |
The light signal in graded index fibre is totally confined due to |
Total inernal reflection
Continuous refraction
Both a and b
Dispersion
|
| 9 |
A spectrometer is used to find |
Wavelength of light
Refractive index of the prism
Angle of minimum deviation of prism
All of these
|
| 10 |
A double convex lens act as a diverging lens when the object is |
Inside the focus
Between f and 2f
At the focus
At a large distance
|
| 11 |
The resolving power of human eye is |
1<span style="color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;">°</span>
2<span style="color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;">°</span>
3<span style="color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;">°</span>
6<span style="color: rgb(0, 0, 0); font-family: Georgia; font-size: 18px; line-height: 23.390625px;">°</span>
|
| 12 |
A fly is sitting on the objective of a telescope pointed towards the moons what effect is impacted in a photograph of the moon taken through the telescope |
The entire field of vision is blocked
There is image of the fly on the photograph
There is no effect at all
There is the reduction in intensity of the image
|
| 13 |
The magnifying power of a simple microscope can be increased if we use eye piece of |
Higher focal length
Smaller focal length
Higher diameter
Smaller diameter
|
| 14 |
In a simple microscope if the final image is located at infinity then its magnifying power is |
25/f
25
f/25
[1 + (25/f)]
|
| 15 |
The object is placed at the principle focus of a simple microscope if the focal length of the lens is 2cm what is the magnifying power of the microscope |
13.5
12.5
Infinity
None of these
|
| 16 |
An object is placed between two parallel mirrors the number of images formed is |
2
4
8
Infinite
|
| 17 |
The bottom of a container filled with liquid appear slightly raised because of |
Refraction
Interference
Diffraction
Reflection
|
| 18 |
The brilliance of diamond is |
Entirely due to refractive index
Entirely due to total internal reflection
Partly due to total internal reflection
None of the above
|
| 19 |
What is the time taken by light to travel 4 mm in a material of refractive index 3 |
4 x 10<sup>-11</sup> s
2 x 10<sup>-11</sup> s
16 x 10<sup>-11</sup> s
8 x 10<sup>-11</sup> s
|
| 20 |
If the power of a lens is 4 diopters then is focal length is |
20 cm
25 cm
50 cm
400 cm
|
| 21 |
Television signal are converted into light signals by |
Decoder
Transistor
Photodiode
Optical fibre
|
| 22 |
In spectrometer the function of collimator is to produce |
Diverging beam of light
Converging beam of light
Parallel beam of light
None of these
|
| 23 |
The wavelength of refractive wave in a denser medium is |
Same as that of the incident wave
Become smaller than the incident
Becomes greater than the incident wave
None of these
|
| 24 |
The minimum distance between a source and the screen for which a real image is possible with a convex lens is |
Its focal length
Twice the focal length
Four times the focal length
Square of the focal length
|
| 25 |
An object is placed at a distance 18 cm from a convex lens. The image is formed at a distance of 9 cm the focal length of the lens is |
6 cm
9 cm
10 cm
18 cm
|
| 26 |
Alexander graham bell transmits a voice message via a |
Beam of light
Telescope
Compound microscope
Mirror
|
| 27 |
In an optical fibre the speed of light is |
Directly proportional to its refractive
Inversely proportional to its refractive inedex
Independent of refractive index
Directly proportional to square of refractive index
|
| 28 |
To get high resolving power for a telescope one should use |
Objective of large aperture
Objective of large focal length
Eye piece of large focal length
Eye piece of small focal length
|
| 29 |
The frequency of light ray is 6 x 1014 Hz. The frequency when it propagates in a medium of refractive index 1.5 will be |
6 x 10<sup>14</sup> Hz
4 x 10<sup>14</sup> Hz
9 x 10<sup>14</sup> Hz
1.67 x 10<sup>14</sup> Hz
|
| 30 |
Rainbow is formed due to combination of |
Dispersion and total internal reflection
Reflection and refraction
Dispersion and focusing
Refection and scattering
|
| 31 |
Spectrum of sun consists of |
Bright lines
Dark lines
Bright bands
Dark bands
|
| 32 |
Focal length of convex lens is maximum for |
Blue light
Yellow light
Green light
Red light
|
| 33 |
Wavelength of light of frequency 100 Hz is |
2 x 10<sup>6 </sup>m
3 x 10<sup>6 </sup>m
4 x 10<sup>6 </sup>m
5 x 10<sup>6 </sup>m
|
| 34 |
One cannot see through fog becuase |
Fog absorbs light
The refractive index of fog is infinity
Light suffers total reflection at the droplet in a fog
Light is scattered by the droplets in fog
|
| 35 |
In young s interference experiment one slit is covered with a cellophane paper which absorbs half the intensity then |
No fringes are observed
All fringes will be darks
bright fringes will be less bright and dark will be less dark
Bright fringes will be brighter and dark fringes will be darks
|
| 36 |
In Newton s rings the central spot appears dark due to |
Phase change
Destructive interference
Small eye piece of optical device
Both a and b
|
| 37 |
Optically active substance are those substance which |
Produce polarization of polarized light
Rotate the plane of polarization of polarized light
Produce double refraction
Both a and b
|
| 38 |
Which of the following is not an application of polarization |
To reduce glare of light
To check concentration sugar in solution
Curtain less windows
All of these
|
| 39 |
A diffraction grating of length 2cm has 4000 lines The grating element is |
0.5 x 10<sup>-2</sup> cm
5 x 10<sup>4</sup>
5 x 10<sup>-4</sup>
0.5 x 10<sup>-4</sup> cm
|
| 40 |
In Michelsons interference the movable mirror is moved and a shift of two fringes is observed then the distance moved by the mirror is |
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None
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