Question # 1

The velocity of light in vacuum can be changed by changing

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Frequency

Amplitude

Wavelength

None of these

Light appears to travel in straight line because

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It is not absorbed by the atmosphere

It is refracted by the atmosphere

Its wavelength is very small

Its velocity is very large

If the object and its image are located at a distance of 5 cm from the focus of a convex lens, the focus length of the lens will be:

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5 cm

10 cm

20 cm

25 cm

Which one of the following can act approximately as a source of monochromatic light;

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Neon lamp

Fluorescent tube

Sodium lamp

None of these

In an interference pattern of Young's double slit(YDS) experiment:

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Bright fringesare wider than dark fringes

Dark fringes are wider than bright fringes

Both dark and bright fringes are of equal width

Central fringes are wider than the outer fringes

The locus of all points in a medium having same phase of vibration is called

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Crest

Trough

Wavelength

Wave-front

A line which represents the direction of travel of a wave is known as:

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Spherical Wavefront

Locus

Ray

Either B or C

Resolving power in mth order diffraction for grating is given by:

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R = N/m

R = m/N

R = N x m

None of these

Monochromatic light means waves of:

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Same frequency

Same colour

Same wavelength

All of them

In case of point, source of light shape of wavefront is:

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Spherical

Cylindrical

Plane

None of these

A convex lens acts as diverging lens when the object is placed:

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Between F and 2F

At 2F

With focal length

Beyond 2F

When the same object is viewed at a shorter distance, the image on the retina of the eye is _____ the so the object appears:

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Greater, smaller

Smaller, smaller

Smaller, larger

Greater, larger

The cause of mirage observed in deserts in bright sunlight is due to

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Refraction of light

Reflection of light

Scattering of light

Total internal reflection of light

If yellow light emitted by sodium lamp in Young's double slit experiment is replaced by blue light of the same intensity

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Fringe width will decrease

Fringe width will increase

Fringe width will remain unchanged

Fringe will become less intense

Stars twinkle due to

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The fact that they do not emit light continuously

The refractive index of earth's atmosphere fluctuates

The Star's atmosphere absorbs its light intermittently

None of these

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