1 |
The light signal in graded index fibre is totally confined due to |
Total inernal reflection
Continuous refraction
Both a and b
Dispersion
|
2 |
A spectrometer is used to find |
Wavelength of light
Refractive index of the prism
Angle of minimum deviation of prism
All of these
|
3 |
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
|
4 |
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>
|
5 |
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
|
6 |
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
|
7 |
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)]
|
8 |
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
|
9 |
An object is placed between two parallel mirrors the number of images formed is |
2
4
8
Infinite
|
10 |
The bottom of a container filled with liquid appear slightly raised because of |
Refraction
Interference
Diffraction
Reflection
|
11 |
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
|
12 |
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
|
13 |
If the power of a lens is 4 diopters then is focal length is |
20 cm
25 cm
50 cm
400 cm
|
14 |
Television signal are converted into light signals by |
Decoder
Transistor
Photodiode
Optical fibre
|
15 |
In spectrometer the function of collimator is to produce |
Diverging beam of light
Converging beam of light
Parallel beam of light
None of these
|
16 |
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
|
17 |
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
|
18 |
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
|
19 |
Alexander graham bell transmits a voice message via a |
Beam of light
Telescope
Compound microscope
Mirror
|
20 |
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
|