Physics Lights and Optics Online Mcqs Test

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Question 1

1. On a rainy day, if there is an oil drop on tar road, colored rings are seen around this drop. This is because of

Answer

Interference pattern produced due to thin oil film

Answer

Total internal reflection of light

Answer

Diffraction pattern

Answer

Polarization

Question 2

2. To demonstrate the phenomenon of interference we require two sources that emit radiation

Answer

Of the same frequency and having definite phase relationship

Answer

Of nearly the same frequency

Answer

Of same frequency

Answer

Different wavelength

Question 3

3. In Michelson interferometer to switch the fringe from bright to dark the mirror should be displaced through

Question 4

4. A point source of light placed in a homogeneous medium gives rise to

Answer

A spherical wave front

Answer

A cylindrical wave front

Answer

An elliptical wave front

Answer

A plane wave front

Question 5

5. Light is a type of energy which produces sensation of

Answer

None of these

Question 6

6. Which one of the following phenomena is not explained by Hygen’s construction of wave front?

Answer

Origin of spectra

Answer

Refraction

Answer

Reflection

Answer

Diffraction

Question 7

7. Which of the following has least wavelength?

Answer

Cosmic-rays

Answer

Ultra-violet rays

Question 8

8. According to Huygen, every point on a wave front may be regarded as a __________ of secondary wavelets.

Question 9

9. Appearance of colour in thin films is due to

Answer

Diffraction

Answer

Polarization

Answer

Interference

Answer

Dispersion

Question 10

10. In Young double slit experiment, if white light is used

Answer

Impossible to predict

Answer

No interference fringes will be seen

Answer

Alternate dark and bright fringes will be seen

Answer

Colored fringes will be seen

Question 11

11. When crest of one wave falls over the trough of the other wave this phenomenon is known as

Answer

Polarization

Answer

Diffraction

Answer

Destructive interference

Answer

Constructive interference

Question 12

12. In the phenomenon of interference, the bright ad dark fringes are of

Answer

Equal width

Answer

None of these

Answer

Different width

Answer

Dark fringes are thicker than bright

Question 13

13. Central spot of New tons rings

Answer

Dart for large wavelength

Answer

Bright for large wavelength

Question 14

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

Answer

Wave front

Answer

Wavelength

Question 15

15. In Young’s experiment, a dark fringe is observed when:

Answer

m Sin θ = (d + 1/2)λ

Answer

½ d Sin θ = mλ

Answer

d Sin θ = (m + 1/2)λ

Answer

2π Sin θ = (m + 1/2)λ

Question 16

16. The condition for constructive interference of two coherent beams is that the path difference should be

Answer

Integral multiple of λ/2

Answer

Integral multiple of λ

Answer

Odd integral multiple of λ/2

Answer

Even integral multiple of λ

Question 17

17. The locus of all points in the same phase of vibration is called:

Answer

Wavelength

Answer

Wave number

Answer

Wave front

Question 18

18. When the two surfaces of a thin film are parallel and the light is incident at a certain angle, _________ fringes are formed.

Answer

Elliptical

Question 19

19. Wave front is the locus of all points in vibration are in the same

Answer

All of these

Answer

Wavelength

Question 20

20. Which effect provides direct experimental evidence that light is a transverse, rather than a longitudinal, wave motion?

Answer

Light can be diffracted

Answer

Two coherent light waves can be made to interfere

Answer

The intensity of light from a point source falls off inversely as the square of the distance from the source

Answer

Light can be polarized

Question 21

21. The principle of Michelson’s interferometers is

Answer

Reflection

Answer

Interference

Answer

Dispersion

Answer

Refraction

Question 22

22. Which one of the following cannot be polarized?

Answer

Ultraviolet rays

Answer

Radio waves

Answer

Sound waves

Question 23

23. The condition for the bright fringes formed due to constructive interference in a diffraction grating is:

Answer

d sin θ = mλ

Answer

d sin θ = 2λm

Answer

md cos θ = λ

Answer

d sin θ = m/2 λ

Question 24

24. Intensities of the two waves of light are l and 4l. The maximum intensity of the resultant wave after superposition is

Question 25

25. The relation of constructive interference in X-ray diffraction is called

Answer

Bragg’s law

Answer

Huygen’s formula

Answer

Compton effect

Answer

Laue’s pattern

Question 26

26. For constructive interference the path difference is

Answer

(m – 1)λ

Question 27

27. In a plane polarized light

Answer

Vibration in two mutually perpendicular directions

Answer

Vibration take place in a direction perpendicular to the direction of propagation of light

Answer

Vibration in all direction

Answer

No vibration at all

Question 28

28. A ____________ lens is used to form Newton’s rings.

Answer

Double-convex

Answer

Plano-convex

Answer

Plano-concave

Answer

Convexo-concave

Question 29

29. A spherical wave front is that which has

Answer

A point source

Answer

A extended source

Answer

None of these

Question 30

30. On a rainy day, if there is an oil drop on tar road, colored rings are seen around this drop. This is because of

Answer

Total internal reflection of light

Answer

Interference pattern produced due to thin oil film

Answer

Diffraction pattern

Answer

Polarization

Question 31

31. If a source of light is moving away from stationary observer, then frequency of light wave appears to change because of

Answer

Interference

Answer

None of these

Answer

Diffraction

Answer

Doppler’s effect

Question 32

32. For the sustained interference of light, the necessary condition is that the two sources should

Answer

Of same amplitude

Answer

Have constant phase difference

Answer

Be close to each other

Question 33

33. In the Michelson Interferometer, if m number fringes pass through a reference point when the mirror is moved a distance d, then the wavelength of the light can be found by the formula:

Answer

λ = 2π dm

Question 34

34. Can two head lights of car can produce interference

Answer

Partly produce interference

Answer

None of these

Question 35

35. Which of the following is conserved when light waves interfere?

Question 36

36. Every point of a wave front may be considered as a

Answer

None of these

Answer

Source of wave front

Answer

Source of secondary wave front

Question 37

37. The contrast in the fringes in any interference pattern depends on

Answer

Wavelength

Answer

Distance between the slits

Answer

Fringe width

Answer

Intensity ratio of the sources

Question 38

38. Polarization occurs only in ________ waves

Answer

Matter waves

Answer

Mechanical waves

Answer

Transverse

Answer

Longitudinal

Question 39

39. If the dark fringe is to be observed then we have relation

Answer

Y = (m + 1) λL/d

Answer

Y = (m + 1/2) λd/L

Answer

Y = (m + ½) dL/λ

Answer

Y = (m + 1/2) λL/d

Question 40

40. The phenomenon of bending of light waves around the edges of an obstacle or a narrow opening is called.

Answer

Transmission

Answer

Refraction

Answer

Reflection

Answer

Diffraction

Question 41

41. Due to Plano convex lens and the plane glass plate the thickness of air film changes from the center to outward

Answer

Increasing gradually

Answer

It is constant at the center

Answer

None of these

Answer

Decreasing gradually

Question 42

42. In Newton’s rings the point of contact of the lend and the glass plate, the air film is

Answer

None of these

Question 43

43. Two sources of light are coherent if they emit rays of

Answer

Same amplitude of vibration

Answer

Same amplitude and wavelength

Answer

Same wave length with constant phase difference

Answer

Same wavelength

Question 44

44. Diffraction fringes are

Answer

Distance between them increases

Answer

Distance between then decreases

Answer

Equally spaced

Answer

They are adjacent with no space in between

Question 45

45. In an interference pattern

Answer

Central fringes are brighter than the outer fringes

Answer

Bright fringes are wider than dark fringes

Answer

Dark fringes are wider than bright fringe

Answer

Both dark and bright fringes are of equal width

Question 46

46. A polarizer is used to

Answer

Produce polarized light

Answer

Increase intensity of light

Answer

Reduced intensity of light

Answer

Produce unpolarised light

Question 47

47. Who devise the experimental arrangement is 1801 for studying interference effects of light?

Answer

None of these

Question 48

48. An oil surface floating on water surface exhibits beautiful colour patter, which is due to

Answer

Reflection of light

Answer

None of these

Answer

Interference of light

Answer

Diffraction of light

Question 49

49. Which of the following properties show light is transverse wave in nature?

Answer

Reflection

Answer

Diffraction

Answer

Interference

Answer

Polarization

Question 50

50. The cause of mirage observed in desert is

Answer

Scattering

Answer

Total internal reflection

Answer

Reflection

Answer

Refraction

Question 51

51. Which effect provides direct experimental evidence that light is a transverse, rather than a longitudinal, wave motion?

Answer

Light can be diffracted

Answer

Light can be polarized

Answer

The intensity of light from a point source falls off inversely as the square of the distance from the source

Answer

Two coherent light waves can be made to interfere

Question 52

52. If the path difference must be half-integral number wavelength

Answer

d sin θ = (m + 1/2)π/λ

Answer

d sin θ = (m + 1/2)λ

Answer

d sin θ = (m + 1)λ

Answer

d in θ = (m + ½ )1/λ

Question 53

53. Diffraction effect is

Answer

More for a round edge

Answer

Less for a round edge

Answer

More for a sharp edge

Answer

Less for a sharp edge

Question 54

54. In Huygen’s wave theory, the locus of all points in the same state of vibration is called

Answer

Wave front

Answer

A half-period zone

Question 55

55. Signal from a remote control to the device operated by it tracels with the speed of:

Answer

Supersonics

Answer

Ultrasonics

Question 56

56. Wavelength of light of frequency 100 Hz is

Answer

2 x 10⁶ m

Answer

4 x 10⁶ m

Answer

3 x 10⁶ m

Answer

5 x 10⁶ m

Question 57

57. The splitting of white light into several colors on passing through a glass prism is due to

Answer

Refraction

Answer

Reflection

Answer

Diffraction

Answer

Interference

Question 58

58. Why laser rays are used to measure long distance?

Answer

Laser rays are high velocity waves

Answer

Laser rays propagate in a straight line

Answer

Laser rays are most coherent waves

Answer

Laser rays are not absorbed

Question 59

59. According to the electromagnetic theory, the speed of light is approximately:

Answer

3.1 x 10⁸ ms¯¹

Answer

3 x 10⁸ ms¯¹

Answer

3 x 10⁵ ms¯¹

Answer

3 x 10¯¹⁰ ms¯¹

Question 60

60. A prism splits a beam of white light into its seven constituent colors. This is so because

Answer

Velocity of different colors is different

Answer

Amplitude of different colors is different

Answer

Energy of different colors is different

Answer

Phase of different colors is different

Question 61

61. Choose the correct statement

Answer

Rays may be normal to wave front

Answer

Rays are normal to wave front

Answer

Rays are not normal to wave front

Answer

There is no relationship between rays and wave fronts

Question 62

62. The idea of light as wave produced by

Answer

Thomos young

Question 63

63. Light on passing through a Polaroid is

Answer

Circularly polarized

Answer

Plane polarized

Answer

Un-polarized

Answer

Elliptically polarized

Question 64

64. When the light is incident on polarizing angle which of the following is completely polarized?

Answer

Refracted light

Answer

Neither reflected nor refracted light

Answer

Both reflected and refracted light

Answer

Reflected light

Answer 201

Refraction

Answer 202

Reflection

Answer 203

Diffraction

Answer 204

Origin of spectra

Answer 205

5 x 10⁵ to 5 x 10⁵ Hz

Answer 206

5 x 10⁵ to 5 x 10¹¹ Hz

Answer 207

5 x 10¹⁴ to 5 x 10¹⁷ Hz

Answer 208

5 x 10¹¹ to 5 x 10¹⁴ Hz

Answer 209

In the form of a narrow beam

Answer 210

Electromagnetic

Answer 211

Incoherent

Answer 212

Monochromatic

Answer 213

It is not absorbed by the atmosphere

Answer 214

Its wavelength is very small

Answer 215

It is reflected by the atmosphere

Answer 216

Its velocity is very large

Answer 217

Reflection

Answer 218

Polarization

Answer 219

Refraction

Answer 220

Diffraction

Answer 221

Of the order of one millimeter

Answer 222

Much larger than the wavelength of light

Answer 223

Of the same order as the wavelength of light

Answer 224

Much smaller than the wavelength of length

Answer 225

Close together

Answer 226

At a far off distance

Answer 227

Coinciding

Answer 228

Opposite to each other

Answer 229

Polarization

Answer 230

Interference

Answer 231

Photoelectric effect

Answer 232

Diffraction

Answer 233

Diffraction

Answer 234

Photoelectric effect

Answer 235

Interference

Answer 236

Polarization

Answer 237

No interference

Answer 238

Interference with bright bands

Answer 239

Interference with dark bands

Answer 240

Interference in which breadth of the fringe will be slightly increase

Answer 241

Polarization

Answer 242

Reflection

Answer 243

Scattering

Answer 244

Diffraction

Answer 245

2 x 10¯⁵ mm

Answer 246

2 x 10¯³ mm

Answer 247

5 x 10¯³ mm

Answer 248

Band absorption spectrum

Answer 249

Line emission spectrum

Answer 250

Band emission spectrum

Answer 251

Line absorption spectrum

Answer 252

Transmission

Answer 253

Polarization

Answer 254

Absorption

Answer 255

Diffraction

Answer 256

Remains the same

Answer 257

None of these

Answer 258

Speed of propagation less than the wave

Answer 259

Speed of propagation greater than wave

Answer 260

Speed of propagation of the wave

Answer 261

Line spectrum

Answer 262

Emission spectrum

Answer 263

Continuous emission spectrum

Answer 264

All of these

Answer 265

Electromagnetic

Answer 266

In the form of a narrow beam

Answer 267

Monochromatic

Answer 268

Incoherent

Answer 269

A longitudinal wave

Answer 270

A transverse waves

Answer 271

A sound wave

Answer 272

An electromagnetic wave

Answer 273

Diffraction grating

Answer 274

Convex lens

Answer 275

Interferometer

Answer 276

None of these

Answer 277

Not comparable

Answer 278

Comparable

Answer 279

Have a lower frequency

Answer 280

Cannot be diffracted

Answer 281

Cannot be polarized

Answer 282

Do not affect a photographic plate

Answer 283

A Plano convex lens and simple glass sheet

Answer 284

A Plano convex lens (long focal length) and the plane of glass plate

Answer 285

None of these

Answer 286

A Plano convex lens and the plane glass plate

Answer 287

Using monochromatic light of higher frequency

Answer 288

Increasing the distance between the slits

Answer 289

Using monochromatic light of longer wavelength

Answer 290

Decreasing the distance between the screen and the slits

Total Questions:	88
Time Allowed:	40 Minutes
Total Marks:	88
How to Attempt Test:	Please choose the right Option in MCQ-type question.
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Physics Lights and Optics Online Mcqs Test

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Important Lights and Optics Question and Answer

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Maan Ali

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