| 1 |
In order to observe interference , the interfering beams must be |
monochromatic
coherent
either of them
both of them
|
| 2 |
A monochromatic source of light gives light of |
one colour
two colours
four colours
seven colours
|
| 3 |
Light waves produce interference when |
source are monochromatic
source are phase coherent
sources are close together
all of them
|
| 4 |
When two light waves travelling in the same direction are out of phase at any point, their resultant amplitude |
increases
decreases
remains unchanged
increases rapidly
|
| 5 |
When the light waves of the same frequency and amplitude travelling in the same direction superimose each other , they give rise to |
interference
diffraction
dispersion
polarization
|
| 6 |
When two lights waves travelling in the same direction are in phase at any point, they producing |
constructive interference
destructive interference
dispersion
polarization
|
| 7 |
The medium in which speed of light is the same in all directions is called |
non-homogeneous medium
homogeneous medium
both of them
empty medium
|
| 8 |
According to the Huygen's principle, the secondary wavelets propagate in the forward direction with a speed equal to |
speed of wave motion
speed of medium
speed of electrons
speed of protons
|
| 9 |
Huygen's principle is used to study the |
formation of wavefronts
propagation of wavefronts
nature of light
speed of light
|
| 10 |
The wave nature of light was first proposed by |
Huygen
Thomas Young
Newton
Compton
|
| 11 |
According to Huygen's principle, the new position of the wavefront after a time can be found by constructing a surface that touches all the |
primary wavelets
secondary wavelets
either of them
none of them
|
| 12 |
According to Huygen's principle, every point of a wavefront may be considered as a source of |
primary wavelets
secondary wavelets
either of them
both of them
|
| 13 |
By which principle we can locate the position of new wavefront after a later time? |
principle of irreversibility
principle of light
Archimedes principle
Huygen's principle
|
| 14 |
A usual way to obtain a plane wave is to place point source of light at the focus of a |
concave lens
convex lens
both of them
either of them
|
| 15 |
In the study of interference and diffraction, we consider |
plane waves
plane wavefronts
both of them
none of them
|
| 16 |
The light form Sun reaches earth in the form of |
plane wavefront
circular wavefront
spherical wavefront
elliptical wavefront
|
| 17 |
A limited region taken on a wavefront which is far away form the source is |
plane wavefront
circular wavefront
spherical wavefront
elliptical wavefront
|
| 18 |
The distance between the concentric wavefronts is |
half wavelength
one wavelength
one and a half wavelength
none of them
|
| 19 |
The waves propagate in space by the motion of the |
wavelengths
frequencies
wavefronts
none of them
|
| 20 |
A line normal to the wavefront including the direction of motion is called |
perpendicular line
parallel line
a ray of light
none of them
|
| 21 |
In case of a point source, the shape of the wavefront is |
straight
elliptical
oval
spherical
|
| 22 |
Such a surface on which all the points have the same phase of vibration is known as |
wavefront
amplitude
displacement
all of them
|
| 23 |
Which characteristics of wave, established the Huygen's wave theory in 1801? |
polarization
interference
propagation
all of them
|
| 24 |
The experimental evidence in support of wave theory in Huygen's time was |
not present
not convincing
convincing
none of them
|
| 25 |
Who proposed that light energy form a luminous source travels in space by means of wave motion? |
Newton
Maxwell
Einstein
Huygen
|
| 26 |
The ratio of kinetic energy to potential energy for solids is |
|
| 27 |
Which of the following pairs is not correct |
Strain - dimensional
Stress - N/m<sup>2</sup>
Modulus of elasticity - N/m<sup>2</sup>
Shear stress - N/m<sup>2</sup>
|
| 28 |
Which of the following is not dimension less |
Poission ration
Sharing strain
Longitudinal strain
Volume stress
|
| 29 |
The modulus of elasticity of material does not depend upon |
Shape
Temperature
Nature of material
Impurities mixed
|
| 30 |
Longitudinal strain can be produced in |
Glass
Water
Honey
Hydrogen gas
|
| 31 |
If the tensile force is suddenly removed from a wire then its temperature will |
Decrease
Increase
Become zero
Remain constant
|
| 32 |
The Hook's law defines |
Modulus of elasticity
Stress
Strain
Elastic limit
|
| 33 |
The shearing strain is measured by |
Angle of rotation
Shearing stress
Angle of shear
Modulus of rigidity
|
| 34 |
If S is the stress and Y is Young's modulus of the material of a wire, the energy stored in the wire per unit volume is |
2 S<sup>2</sup>Y
S<sup>2</sup>/2Y
2Y/S<sup>2</sup>
S/2Y
|
| 35 |
|
|
| 36 |
On applying a stress of 20 x 108Nm-2, the length of perfectly elastic wire is doubled. Its young' modulus is |
40 x 10<sup>8 </sup>N/m<sup>2</sup>
20 x 10<sup>8</sup>N/m<sup>2</sup>
10 x 10<sup>8</sup>N/m<sup>2</sup>
5 x 10<sup>8</sup>N/m<sup>2</sup>
|
| 37 |
A certain force F increases the length of a wire by 1 mm. The force required to increase its length by 2mm is |
2 F
4 F
8 F
16 F
|
| 38 |
A bar of length L, cross-section A and Young's modulus Y, is pulled by a force F from both ends so as to produce an elongation x. Then: |
x<span style="color: rgb(34, 34, 34); font-family: "Times New Roman"; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);"><i>∝</i></span>1/L
x<span style="color: rgb(34, 34, 34); font-family: "Times New Roman"; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);"><i>∝</i></span>A
x<span style="color: rgb(34, 34, 34); font-family: "Times New Roman"; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);"><i>∝</i></span>1/A
x<span style="color: rgb(34, 34, 34); font-family: "Times New Roman"; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);"><i>∝</i></span>Y
|
| 39 |
The young's modulus of a wire of length L and radius 'r' is Y. If the length is reduced to L/2 and radius to r/2, its Young's modulus will be |
Y/2
Y
2Y
4Y
|
| 40 |
Energy per unit volume of a stretched wire is |
(1/2) x load x extension
Load x stress
Stress x strain
(1/2) x stress x strain
|