| 1 |
A polarizer is used to |
Reduced intensity of light
Produce polarized light
Increase intensity of light
Produce unpolarised light
|
| 2 |
In young's double slit experiment the separation between the slit is halved and distance between the slit and screen is doubled.The fringe width is |
Unchanged
Halved
Doubled
Quadrupled
|
| 3 |
Plane microwaves are incident on a long slit having a width of 5 cm.The wavelength of the microwaves if the first minima is formed at 30° is |
25 cm
5 cm
2.5 cm
5 mm
|
| 4 |
Which of the following properties show light is transverse wave in nature? |
Interference
Reflection
Diffraction
Polarization
|
| 5 |
To demonstrate the phenomenon of interference we require two sources that emit radiation |
Of same frequency
Different wavelength
Of the same frequency and having definite phase relationship
Of nearly the same frequency
|
| 6 |
The tip of a needle does not give a sharp image it is due to |
Polarization
Interference
Diffraction
None of these
|
| 7 |
Which effect provides direct experimental evidence that light is a transverse rather than a longitudinal wave motion? |
Light can be diffracted
Two coherent light waves can be made to interfere.
The intensity of light from a point source falls off inversely as the square of the distance from the source
Light can be polarized
|
| 8 |
Two monochromatic radiations X and Y are incident normally on a diffraction grating.The second order intensity maximum for X coincides with the third order intensity maximum for Y what is the ratio wavelength of X/wavelength of Y? |
1/2
2/3
3/2
2/1
|
| 9 |
Which of the following gives three regions of the electromagnetic spectrum in order of increasing wavelength? |
Gamma rays,microwaves,visible radiation
Ultraviolet infra-red microwaves
Radio waves ultraviolet X-rays
Visible radiation gamma rays radio waves
|
| 10 |
Which effect provides direct experiment evidence that light is a transverse rather than a longitudinal,wave motion? |
Light can be diffracted
Two coherent light waves can be made to be interfere
The intensity of light from a point source falls off inversely as the square of the distance from the source
Light can be polarized
|
| 11 |
Ultra-violet rays differ from X-rays in that ultra - violet rays |
Cannot be diffracted
Cannot be polarized
Do not affect a photographic plate
Have a lower frequency
|
| 12 |
Which of the following frequency ranges includes most of the electromagnetic waves emitted by the ultra - violet tubes used in a sun bed? |
5 x 10<sup>5</sup> to 5 x 10<sup>8</sup> Hz
5 x 10<sup>8</sup> to 5 x 10<sup>11</sup> Hz
5 x 10<sup>11</sup> to 5 x 10<sup>14</sup> Hz
5 x 10<sup>14</sup> to 5 x 10<sup>17</sup> Hz
|
| 13 |
In a spectrometer experiment monochromatic light is incident normally on a diffraction grating having 4.5 x 105 lines per meter.The second order line is seen at an angle of 30 to the normal what is the wavelength of the light? |
200 nm
430 nm
500 nm
556 nm
|
| 14 |
In young's slit experiment on interference the ratio of the intensities of a bright band and a dark band is 6 : 1 the ratio of the amplitudes o the interfering waves is |
16
5/3
4
1/4
|
| 15 |
Signal from a remote control to the device operated by it travels with the speed of: |
Sound
Light
Ultrasonics
Supersonics
|
| 16 |
When the light is incident on polarizing angle which of the following is completely polarized? |
Reflected light
Refracted light
Both reflected and refracted light
Neither reflected nor refracted light
|
| 17 |
In the Young's double slit experiment the separation between the slits is halved and the distance between the slits and the screen is doubled the fringe width is |
Halved
Unchanged
Doubled
Quadrupled
|
| 18 |
For the sustained interference of light the necessary condition is that the two sources should |
Have constant phase difference
Be narrow
Be close to each other
Of same amplitude
|
| 19 |
If a source of light is moving away from stationary observer then frequency of light wave appears to change because of |
Doppler's effect
Interference
Diffraction
None of the above
|
| 20 |
When seen in green light the saffron and green portions of our National Flag will appear to be |
Black
Black and green respectively
Green
Green and yellow respectively
|
| 21 |
Ray optics is valid,when characteristic dimensions are |
Of the same order as the wavelength of light
Much smaller than the wavelength of length
Of the order of one millimeter
Much larger than the wavelength or light
|
| 22 |
When light travels from one medium to another which are separated by a sharp boundary the characteristic which does not change is |
Velocity
Wavelength
Frequency
Amplitude
|
| 23 |
Fraunhofer spectrum is a |
Line absorption spectrum
Band absorption spectrum
Line emission spectrum
Band emission spectrum
|
| 24 |
The sky appears blue because |
Red light is absorbed
Blue light is scattered the most
Blue light is absorbed
It is its natural color
|
| 25 |
Huygen's wave theory of light cannot explain |
Diffraction
Interference
Polarization
Photoelectric effect
|
| 26 |
The contrast in the fringes in any interference pattern depends on |
Frings width
Intensity ratio of the sources
Distance between the slits
Wavelength
|
| 27 |
Which one of the following phenomena is not explained by Huygen's construction of wavefront? |
Refraction
Reflection
Diffraction
Origin of spectra
|
| 28 |
Light appears to travels in straight lines since |
It is not absorbed by the atmosphere
It is reflected by the atmosphere
Its wavelength is very small
Its velocity is very large
|
| 29 |
The twinkling of stars is due to |
The fact that stars do not emit light continususly
The refractive index of the earth's atmosphere fluctuate
Intermittent absorption of star light by its own atmosphere
None of these
|
| 30 |
A prism splits a beam of white light into its seven constituent colors.This is so because |
Phase of different colors is diferent
Amplitude of different colors is different
Energy of different colors is different
Velocity of different colors if different
|
| 31 |
A sun rise or sun set the sun looks reddish because |
The sun is coldest at these times
Of the effects of reflection and refraction
The sun is hottest at these times
Of the scattering of light
|
| 32 |
One cannot see through fog because |
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
|
| 33 |
Stress beyond which a permanent deformation is observed in a body is called |
Minimum stress
Maximum
Yield stress
Plastic stress
|
| 34 |
Substance which break just after the elastic limit is crossed are called |
Soft subtances
Hard substances
Brittle substances
Ductile substances
|
| 35 |
If stress is increased beyond the elastic limit a permanent change in the material is observed This behavior is called |
Elastic deformation
Elasticity
Plasticity
Yield strength
|
| 36 |
Stress that induces a change in the shape of the body is named as |
Tensile stress
Volumetric stress
Shear stress
None of these
|
| 37 |
Upon applying some unbalanced external stress the deformation may be observed in |
Length
Surface area
Volume
All of these
|
| 38 |
The atoms or molecules in a crystalline solid are held together by |
Attractive force
Gravitational force
Cohesive force
Electromagnetic force
|
| 39 |
The limit below which the Hooke s law holds well is called |
Yield point
Breaking stress
Tensile strength
Elastic limit
|
| 40 |
Steel is more elastic than rubber because |
It is a metal
Its density is higher
Ratio of stress to strain is more
Ratio of stress to strain is less
|