Physics Lights and Optics Online Mcqs Test

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Question 1

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

Answer

Diffraction

Answer

Refraction

Answer

Origin of spectra

Answer

Reflection

Question 2

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

Answer

All of these

Answer

Wavelength

Question 3

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

Answer

Plano-concave

Answer

Plano-convex

Answer

Double-convex

Answer

Convexo-concave

Question 4

4. Curtain less windows are made by making use of __________ of light.

Answer

Polarization

Answer

Diffraction

Answer

Transmission

Answer

Absorption

Question 5

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

Answer

Diffraction of light

Answer

None of these

Answer

Reflection of light

Answer

Interference of light

Question 6

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

Answer

Diffraction

Answer

Constructive interference

Answer

Destructive interference

Answer

Polarization

Question 7

7. Crystals of a material can behave as

Answer

Convex lens

Answer

Diffraction grating

Answer

Interferometer

Question 8

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

Answer

2π Sin θ = (m + 1/2)λ

Answer

½ d Sin θ = mλ

Answer

m Sin θ = (d + 1/2)λ

Answer

d Sin θ = (m + 1/2)λ

Question 9

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

Answer

Laue’s pattern

Answer

Huygen’s formula

Answer

Compton effect

Answer

Bragg’s law

Question 10

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

Answer

None of these

Answer

Source of secondary wave front

Answer

Source of wave front

Question 11

11. Which of the following has least wavelength?

Answer

Ultra-violet rays

Answer

Cosmic-rays

Question 12

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

Answer

A cylindrical wave front

Answer

A plane wave front

Answer

An elliptical wave front

Answer

A spherical wave front

Question 13

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

Answer

Of nearly the same frequency

Answer

Of the same frequency and having definite phase relationship

Answer

Of same frequency

Answer

Different wavelength

Question 14

14. The light produced by a laser is all the following except

Answer

Monochromatic

Answer

In the form of a narrow beam

Answer

Electromagnetic

Answer

Incoherent

Question 15

15. Coherent monochromatic light illuminates two narrow parallel slits and the interference pattern that results is observed on a screen some distance beyond the slits. Which modification increases the separation between the dark lines of the interference pattern?

Answer

Using monochromatic light of higher frequency

Answer

Decreasing the distance between the screen and the slits

Answer

Using monochromatic light of longer wavelength

Answer

Increasing the distance between the slits

Question 16

16. Which one of the following cannot be polarized?

Answer

Ultraviolet rays

Answer

Sound waves

Answer

Radio waves

Question 17

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

Answer

None of these

Question 18

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

Answer

Wavelength

Answer

Wave number

Answer

Wave front

Question 19

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

Answer

Interference

Answer

Refraction

Answer

Reflection

Answer

Diffraction

Question 20

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

Answer

None of these

Answer

It is constant at the center

Answer

Increasing gradually

Answer

Decreasing gradually

Question 21

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

Answer

3 x 10¯¹⁰ ms¯¹

Answer

3.1 x 10⁸ ms¯¹

Answer

3 x 10⁵ ms¯¹

Answer

3 x 10⁸ ms¯¹

Question 22

22. Wavelength of light of frequency 100 Hz is

Answer

4 x 10⁶ m

Answer

3 x 10⁶ m

Answer

2 x 10⁶ m

Answer

5 x 10⁶ m

Question 23

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

Answer

Two coherent light waves can be made to interfere

Answer

Light can be diffracted

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 24

24. Longitudinal waves do not exhibit

Answer

Diffraction

Answer

Refraction

Answer

Polarization

Answer

Reflection

Question 25

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

Answer

Be close to each other

Answer

Of same amplitude

Answer

Have constant phase difference

Question 26

26. The principle of Michelson’s interferometers is

Answer

Dispersion

Answer

Refraction

Answer

Interference

Answer

Reflection

Question 27

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

Answer

Same amplitude and wavelength

Answer

Same wavelength

Answer

Same wave length with constant phase difference

Answer

Same amplitude of vibration

Question 28

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

Answer

Wavelength

Answer

Wave front

Question 29

29. Ray optics is valid, when characteristic dimensions are

Answer

Much smaller than the wavelength of length

Answer

Much larger than the wavelength of light

Answer

Of the order of one millimeter

Answer

Of the same order as the wavelength of light

Question 30

30. Interference was observed in interference chamber, when air was present, now the chamber is evacuated and if the same light is used, a careful observer will see

Answer

Interference in which breadth of the fringe will be slightly increase

Answer

No interference

Answer

Interference with bright bands

Answer

Interference with dark bands

Question 31

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

Answer

Supersonics

Answer

Ultrasonics

Question 32

32. A spectrum which contains all wavelengths without any break is called

Answer

All of these

Answer

Line spectrum

Answer

Continuous emission spectrum

Answer

Emission spectrum

Question 33

33. Diffraction fringes are

Answer

They are adjacent with no space in between

Answer

Distance between then decreases

Answer

Equally spaced

Answer

Distance between them increases

Question 34

34. A polarizer is used to

Answer

Increase intensity of light

Answer

Produce unpolarised light

Answer

Produce polarized light

Answer

Reduced intensity of light

Question 35

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

Question 36

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

Answer

Impossible to predict

Answer

Alternate dark and bright fringes will be seen

Answer

No interference fringes will be seen

Answer

Colored fringes will be seen

Question 37

37. The idea of light as wave produced by

Answer

Thomos young

Question 38

38. Light on passing through a Polaroid is

Answer

Un-polarized

Answer

Plane polarized

Answer

Elliptically polarized

Answer

Circularly polarized

Question 39

39. 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 40

40. Huygen’s wave theory of light cannot explain

Answer

Interference

Answer

Polarization

Answer

Photoelectric effect

Answer

Diffraction

Question 41

41. Fraunhoffer’s lines commonly visible in the sun’s spectrum are examples of

Answer

Line emission spectrum

Answer

Line absorption spectrum

Answer

Band emission spectrum

Answer

Band absorption spectrum

Question 42

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

Question 43

43. Diffraction effect is

Answer

Less for a round edge

Answer

More for a sharp edge

Answer

Less for a sharp edge

Answer

More for a round edge

Question 44

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

Question 45

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

Answer

Reflected light

Answer

Neither reflected nor refracted light

Answer

Both reflected and refracted light

Answer

Refracted light

Question 46

46. Which of the following frequency ranges includes most of the electromagnetic waves emitted by the ultra – violet tubes used in a sun bed?

Answer

5 x 10¹¹ to 5 x 10¹⁴ Hz

Answer

5 x 10⁵ to 5 x 10⁵ Hz

Answer

5 x 10⁵ to 5 x 10¹¹ Hz

Answer

5 x 10¹⁴ to 5 x 10¹⁷ Hz

Question 47

47. For constructive interference the path difference is

Answer

(m – 1)λ

Question 48

48. A thin film is a transparent medium whose thickness with the wavelength of light are

Answer

Not comparable

Answer

None of these

Answer

Comparable

Question 49

49. The setting of Newton’s rings is

Answer

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

Answer

A Plano convex lens and simple glass sheet

Answer

None of these

Answer

A Plano convex lens and the plane glass plate

Question 50

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

Answer

Different width

Answer

None of these

Answer

Equal width

Answer

Dark fringes are thicker than bright

Question 51

51. If a wave can be polarized, it must be

Answer

A longitudinal wave

Answer

A transverse waves

Answer

A sound wave

Answer

An electromagnetic wave

Question 52

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

Answer

Fringe width

Answer

Wavelength

Answer

Distance between the slits

Answer

Intensity ratio of the sources

Question 53

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

Answer

Y = (m + 1/2) λL/d

Answer

Y = (m + 1/2) λd/L

Answer

Y = (m + 1) λL/d

Answer

Y = (m + ½) dL/λ

Question 54

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

Answer

None of these

Question 55

55. Polarization occurs only in ________ waves

Answer

Longitudinal

Answer

Mechanical waves

Answer

Matter waves

Answer

Transverse

Question 56

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

Question 57

57. Can two head lights of car can produce interference

Answer

Partly produce interference

Answer

None of these

Question 58

58. 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

Polarization

Answer

Interference pattern produced due to thin oil film

Answer

Diffraction pattern

Question 59

59. In a plane polarized light

Answer

No vibration at all

Answer

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

Answer

Vibration in all direction

Answer

Vibration in two mutually perpendicular directions

Question 60

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

Answer

Laser rays are high velocity waves

Answer

Laser rays are most coherent waves

Answer

Laser rays propagate in a straight line

Answer

Laser rays are not absorbed

Question 61

61. 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 62

62. The fringe spacing in case of blue light

Answer

None of these

Answer

Remains the same

Question 63

63. 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

Diffraction pattern

Answer

Total internal reflection of light

Answer

Interference pattern produced due to thin oil film

Answer

Polarization

Question 64

64. Central spot of New tons rings

Answer

Bright for large wavelength

Answer

Dart for large wavelength

Answer 204

d sin θ = (m + 1/2)π/λ

Answer 205

d in θ = (m + ½ )1/λ

Answer 206

d sin θ = (m + 1)λ

Answer 207

d sin θ = (m + 1/2)λ

Answer 208

Monochromatic

Answer 209

Incoherent

Answer 210

Electromagnetic

Answer 211

In the form of a narrow beam

Answer 212

Total internal reflection

Answer 213

Refraction

Answer 214

Scattering

Answer 215

Reflection

Answer 216

d sin θ = m/2 λ

Answer 217

d sin θ = mλ

Answer 218

md cos θ = λ

Answer 219

d sin θ = 2λm

Answer 220

Interference

Answer 221

None of these

Answer 222

Doppler’s effect

Answer 223

Diffraction

Answer 224

Dispersion

Answer 225

Polarization

Answer 226

Diffraction

Answer 227

Interference

Answer 228

Transmission

Answer 229

Reflection

Answer 230

Refraction

Answer 231

Diffraction

Answer 232

Do not affect a photographic plate

Answer 233

Cannot be polarized

Answer 234

Cannot be diffracted

Answer 235

Have a lower frequency

Answer 236

None of these

Answer 237

A extended source

Answer 238

A point source

Answer 239

It is not absorbed by the atmosphere

Answer 240

Its wavelength is very small

Answer 241

It is reflected by the atmosphere

Answer 242

Its velocity is very large

Answer 243

Opposite to each other

Answer 244

Coinciding

Answer 245

At a far off distance

Answer 246

Close together

Answer 247

Polarization

Answer 248

Diffraction

Answer 249

Interference

Answer 250

Photoelectric effect

Answer 251

Odd integral multiple of λ/2

Answer 252

Even integral multiple of λ

Answer 253

Integral multiple of λ/2

Answer 254

Integral multiple of λ

Answer 255

Bright fringes are wider than dark fringes

Answer 256

Central fringes are brighter than the outer fringes

Answer 257

Dark fringes are wider than bright fringe

Answer 258

Both dark and bright fringes are of equal width

Answer 259

Rays are not normal to wave front

Answer 260

Rays are normal to wave front

Answer 261

There is no relationship between rays and wave fronts

Answer 262

Rays may be normal to wave front

Answer 263

None of these

Answer 264

Polarization

Answer 265

Reflection

Answer 266

Diffraction

Answer 267

Scattering

Answer 268

Light can be diffracted

Answer 269

Light can be polarized

Answer 270

Two coherent light waves can be made to interfere

Answer 271

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

Answer 272

Elliptical

Answer 273

Polarization

Answer 274

Interference

Answer 275

Reflection

Answer 276

Diffraction

Answer 277

Energy of different colors is different

Answer 278

Phase of different colors is different

Answer 279

Amplitude of different colors is different

Answer 280

Velocity of different colors is different

Answer 281

5 x 10¯³ mm

Answer 282

2 x 10¯⁵ mm

Answer 283

2 x 10¯³ mm

Answer 284

Reflection

Answer 285

Origin of spectra

Answer 286

Refraction

Answer 287

Diffraction

Answer 288

Speed of propagation of the wave

Answer 289

Speed of propagation greater than wave

Answer 290

Speed of propagation less than the wave

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

Physics Lights and Optics Practice Test Online With Explanation

Physics

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Key Preparation Tips:

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Maan Ali

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