| 1 |
The superposition of the two waves of same frequency and amplitude travelling in the same direction gives rise to an effect called: |
Diffraction
Interference
Polarization
Dispersion
|
| 2 |
The locus of all points in a medium having same phase of vibration is called: |
Crest
Trough
Wavelength
Wavefront
|
| 3 |
According to Huygen's principle: |
Light travel in straight line
Light is a transvers wave
Light has dual nature
All point on the primary wavefront are the sources of secondary wavelets
|
| 4 |
The cause of mirage observed in deserts in bright sunlight is due to: |
Refraction of light
Reflection of light
Scattering of light
Total internal reflection of light
|
| 5 |
The velocity of light in vacuum can be changed by changing: |
Frequency
Amplitude
Wavelength
None of these
|
| 6 |
The image of the tip of a needle is never sharp because of |
Polarization of light
Interference of light
Diffraction of light
Reflection of light
|
| 7 |
Which one the following gives three regions of electromagnetic sepctrum in order of increasing wavelength? |
Gamma rays, micro waves, visible light
Radio waves, ultraviolet waves, X-rays
Ultraviolet rays, Infrared rays, micro waves
Visible light, gamma rays, radio waves
|
| 8 |
Huygen's theory cannot explain: |
Diffraction
Interference
Polarization
Photoelectric effect
|
| 9 |
The contrast in the fringes in an interference pattern depends upon |
Fringe width
Relative intensities of the two sources
Distance between the slits
Wavelength
|
| 10 |
If yellow light emitted by sodium lamp in Young's double slit experiment is replaced by blue light of the same intensity: |
Fringe width will decrease
Fringe width will increase
Fringe width will remain unchanged
Fringe will become less intense
|
| 11 |
Which one of the following phenomenon cannot be explained on the bases of Huygen's theory? |
Refraction
Reflection
Diffraction
Formation of spectrum
|
| 12 |
Light appears to travel in straight line because |
It is not absorbed by the atmosphere
It is refracted by the atmosphere
Its wavelength is very small
Its velocity is very large
|
| 13 |
Star twinkle due to |
The fact that they do not emit light continously
The refractive index of earth's atmosphere fluntuates
The star's atmosphere absorbs its light intermittently
None of these
|
| 14 |
A prism splits a beam of white light into seven component colors. This is so because |
Phase of different colors is different
Amplitude of different colors is different
Energy of different colors is different
Velocity of different colors is different
|
| 15 |
The main reason for the high speed of bullet train is |
Magnetic effect
Reduced friction
Design of train
None of these
|
| 16 |
A bullet train move with the velocity of |
400 Kmh<sup>-1</sup>
460 Kmh<sup>-1</sup>
500 Kmh<sup>-1</sup>
510 Kmh<sup>-1</sup>
|
| 17 |
A material most suitable to make the permanent magnet are |
High retentivity
Large coercive current
Small domain friction
a and b
|
| 18 |
The area of the loop is the dissipated energy which do work against friction of domains is called |
Current loss
Voltage loss
Hysteresis loss
None of these
|
| 19 |
The energy need to magnetize and demagnetize the specimen during the each cycle of magnetizing current is |
Value of current
Value of demagnetizing current
Value of magnetic flux density
Area of the loop
|
| 20 |
Hysteresis is the loop in which the material is magnetized and its curve never pass through |
The same line
One side of origin
Origin
None of these
|
| 21 |
A current which demagnetize the material completely is called |
Applied current
Coercive current
Maximum current
None of these
|
| 22 |
Remanance or Retentivity is the phenomenon in which the material still remains strongly magnetized when curve is |
Increase to maximum
Reduce to minimum
Reduce to zero
None of these
|
| 23 |
The saturation of the material reached when magnetic flux density changes from |
Zero to minimum value
Zero to maximum value
Maximum to zero value
Minimum to negative value
|
| 24 |
In the phenomenon of hysteresis, the magnetism and magnetizing current behaves as |
I lags
1 leads B
I & B becomes equal
None of these
|
| 25 |
The curie temperature of iron is |
600 C<sup>o</sup>
650 C<sup>o</sup>
700 C<sup>o</sup>
750 C<sup>o</sup>
|
| 26 |
A temperature at which the material losses its orderliness is know as |
Ambient temperature
Curie temperature
Highest temperature
None of these
|
| 27 |
Hard magnetic materials are |
Iron
Steel
Alnico
None of these
|
| 28 |
A special alloy called Alnico is known as |
Soft magnetic material
Hard magnetic material
In between soft and hand magnetic material
None of these
|
| 29 |
The combination of solenoid and a specimen of iron inside it make a power full magnet called |
Horse shoe magnet
Bar magnet
Electromagnet
10<sup>-10</sup> to 10<sup>18</sup>
|
| 30 |
Each domain contains the atoms of range of |
10<sup>-10</sup> to 10<sup>18</sup>
10<sup>10</sup> to 10<sup>16</sup>
10<sup>12</sup> to 10<sup>17</sup>
10<sup>12</sup> to 10<sup>16</sup>
|
| 31 |
The domains are the small regions of the order of |
Millimeter
Micrometer
Micron
None of these
|
| 32 |
Ferromagnetic materials are those in which atoms cooperate with each other |
Weakly
Strongly
Moderately
None of these
|
| 33 |
The motion of a charged nucleus also produces a magnetic field which is |
Weaker than orbital electrons
Stronger than orbital electrons
Equal than orbital electrons
None of these
|
| 34 |
The examples of diamagnetic substances |
Water
Copper
Antimony
All of them
|
| 35 |
Diamagnetic substances are those in which |
Spin and orbital motions are supported
Spin and orbital motions are opposed
Resultant of spin and orbital motion is zero
None of these
|
| 36 |
Paramagnetic substances are those in which |
Spin and orbital motions are supported
Spin and orbital motions are opposed
Spin and orbital motions supported a little
None of these
|
| 37 |
An atom in which there is a resultant magnetic field behave like a |
Tiny magnet
Magnetic dipole
No magnet
a and b
|
| 38 |
The magnetism produced by electrons within an atom is due to |
Spin motion
Orbital motion
Spin and orbital motion
None of these
|
| 39 |
The magnetism produced by electrons within an atom from motion/motions of electron. |
One motion
Two motions
Three motions
None of these
|
| 40 |
The magnetic field produced due to circulating currents. The idea was first given by |
Faraday
Ampere
Lenz
None of these
|