Light: MCQ Test (50 questions)

Question 1 of 50

The wave theory of light was established by whom?

ANewton
BHuygens
CPlank
DFaraday

Question 2 of 50

Which of these is correct?

A1/f=1/u=1/v
Bf=D/2
C1/f-1/u+1/v
Df=u+v

Question 3 of 50

The sky appears blue because-

ABlue light is scattered the most.
BRed light is scattered the most.
CBlue light is least absorbed in the atmosphere
DRed light is absorbed the most in the atmosphere.

Question 4 of 50

A lemon kept in a glass of water appears larger than its actual size, why does this happen?

Areflection of light
Bscattering of light
Crefraction of light
Dpolarization of light

Question 5 of 50

Some transport vehicles have additional yellow lights. This is done because:

AThe vehicle looks beautiful when the light is yellow.
BYellow light consumes less electrical energy
CYellow light penetrates fog, making the road clearer, so yellow lights are useful on foggy nights.
DYellow light does not glare at the eyes of people walking on the road

Question 6 of 50

There are three basic colours-

Agreen, yellow, red
BBlue, Yellow, Red
CBlue, Red, Green
DBlue, Yellow, Green

Question 7 of 50

Who discovered the electromagnetic nature of light?

ASnell
BNewton
CMaxwell
DYoung

Question 8 of 50

The primary colour is-

Acolors found in nature
Brainbow colors
Ccolors of the spectrum of white light
DColors that cannot be produced by mixing other colors.

Question 9 of 50

Why does dry sand appear shiny, while wet sand is dull?

Ait's an optical illusion
BThis is because of reflection
CThis is due to refraction
DThis is due to scattering

Question 10 of 50

Why does a cut diamond sparkle?

ADue to its molecular structure
Bdue to the absorption of light
Cdue to total internal reflection
Ddue to some other inherent quality

Question 11 of 50

Who first discovered the speed of light?

AGalileo
BNewton
CRomer
DMichaelson

Question 12 of 50

Internal reflection of light from the sun can occur if the light-

Ago from air to glass
Bgo from air to water
Cgo from glass to air
Dgo from water to glass

Question 13 of 50

Which of the following colours of light diverges the least through a prism?

ARed
BGreen
CPurple
DYellow

Question 14 of 50

What confirms the particle nature of radiation?

Ainterference
Bphotoelectric effect
CDiffraction
Dpolarization

Question 15 of 50

Lunar eclipse occurs in-

Aon the new moon day
Bfull moon day
CNew moon and full moon days
Dcrescent moon day

Question 16 of 50

Due to what does the sky appear blue?

ARefraction
Breflection
Cscattering
Ddeflection

Question 17 of 50

If a person stands between two plane mirrors inclined at an angle of 60°, how many images will he see?

A3
B4
C5
D6

Question 18 of 50

When red glass is heated at high temperature, it will appear-

ARed
BGreen
CBlue
DYellow

Question 19 of 50

If the speed (movement) of light in air is 3x108m/sec, what will be the speed of light in a medium whose refractive index is 1⁄2?

A2x18m/s
B9 /4x18m/s
C3/2x18m/s
D3x18m/s

Question 20 of 50

How will a plant with green leaves look when kept in red light?

AGreen
BPurple
CBlack
DRed

Question 21 of 50

What does a watchmaker use to look at the fine parts of a watch?

Aphoto camera
Bmagnifying lens
Ccompound microscope
DVisionary

Question 22 of 50

Which of the following colour combinations is most convenient during day and night?

AOrange and blue
Bwhite and black
CYellow and Blue
Dred and green

Question 23 of 50

Hypermetropia means-

Anearsightedness
Bfarsightedness
Ca little far sight
DPresbyopia

Question 24 of 50

What is the defect of vision called in which points in one plane of a substance appear to be in the centre, while points in the other plane appear to be off the centre?

Along view
Bdistortion
Cindistinctness
Dnearsightedness

Question 25 of 50

Assertion (A): Danger signal is made red in colour. Reason (R): Red colour has the least scattering. Code:

ABoth A and R are correct and R is the correct explanation of A
BBoth A and R are correct, but R is not the correct explanation of A
CA is correct, but R is incorrect
DA is wrong, but R is correct

Question 26 of 50

Which lens is used in the spectacles of a person suffering from farsightedness?

Aconvex lens
Bconcave lens
Cflat lens
Dplano-concave lens

Question 27 of 50

We see the colour of grass as green because-

AIt reflects green light back to our eyes.
BIt reflects white light onto our eyes.
CIt reflects all light except green.
DIt absorbs green light

Question 28 of 50

The nature of light radiation is-

Awave-like
Bparticle-like
Clike both waves and particles
Dnot like a wave or a particle

Question 29 of 50

Consider the following phenomena: 1. Size of the Sun at dusk 2. Colour of the Sun at dawn 3. Appearance of the Moon at dawn 4. Twinkling of stars in the sky 5. Appearance of the Pole Star in the sky Which of the above are optical illusions?

A1, 2 and 3
B3, 4 and 5
C1, 2 and 4
D2, 3 and 5

Question 30 of 50

Which one of the following is used in making periscope?

Aconcave lens
Bconcave mirror
Cplane mirror
DNone of these

Question 31 of 50

Which of the following statements is not correct for light rays?

Alight travels at different speeds in different media
BLight travels in air at a speed of about 300 million meters per second
CAs light leaves the surface of water and enters the air, its speed slows down
DAs light leaves the glass surface and enters the air, its speed increases

Question 32 of 50

In what form does the signal travel in fibre optical communication?

Alight wave
Bradio waves
Cmicrowave
Delectric wave

Question 33 of 50

Which secondary color is obtained by mixing two primary colors, red and blue?

AWhite
BYellow
CMagenta
DCyan

Question 34 of 50

Which of the following is correct regarding the formula 1/f=1/v=1/u according to the Cartesian sign convention, where the symbols have their usual meanings?

AThis applies only to spherical mirrors.
BThis applies only to spherical lenses.
CThis applies to spherical mirrors as well as spherical lenses.
DThis is an invalid formula lens, concave, and has a focal length of 2.0 m.

Question 35 of 50

What is the phenomenon called that creates a mirage?

Ainterference
BDiffraction
Cpolarization
Dtotal internal reflection

Question 36 of 50

When a convex lens is immersed in water, its capacity-

Adecreases
Bincreases
Cremains unchanged
Dnone of these

Question 37 of 50

Wood immersed in water appears bent. This appearance is due to the following reasons:

Areflection of light
BDiffraction of light
Crefraction of light
DImmersion of light

Question 38 of 50

What is the name of the phenomenon (driven by the scattering of light) that causes mountain tops to turn pink or orange at sunrise and sunset?

ABrillouin scattering
Bstate of confusion
CAlpenglow
DBarrel distortion

Question 39 of 50

The bending of light from the edge of an obstacle is called-

Adeflection
BDiffraction
CRefraction
Dinterference

Question 40 of 50

Which of the following phenomena does not occur in both light and sound?

ADiffraction
Bpolarization
Creflection
DRefraction

Question 41 of 50

When a compact disc (CD) is viewed in sunlight, a rainbow-like display of colors is seen. This can be explained by—

ABased on the phenomena of reflection and diffraction
BBased on the phenomena of reflection and transmission
CBased on the phenomena of diffraction and transmission
DBased on the phenomena of refraction, diffraction and transmission

Question 42 of 50

Sodium vapour lamps are often used for street lighting because-

AThese are cheap.
BTheir light is monochromatic and does not split when passing through water droplets.
CThese are cool to the eyes
DThese give bright light.

Question 43 of 50

What causes a rainbow?

ARefraction and Dispersion
BScattering and refraction
CDiffraction and refraction
DRefraction and reflection

Question 44 of 50

When the sun is near the horizon, that is, in the morning and evening, it appears reddish. What is the reason for this?

ARed light is least scattered by the atmosphere
BRed light is scattered the most by the atmosphere
CThis is the color of the sun in the morning and evening.
DEarth's atmosphere emits red light

Question 45 of 50

The image formed on the retina is-

AEqual to the object but inverted
Bsmaller than the object but straight
Cparallel to but perpendicular to the object
Dsmaller than the object but opposite

Question 46 of 50

Which lens can correct colour blindness?

Aconcave lens
Bconvex lens
Ccylindrical lens
Dnone of these

Question 47 of 50

What is the function of the iris?

Acontrolling the amount of light entering the eye
BReducing the amount of light entering the eye
Csending images to the image lens
Dnone of these

Question 48 of 50

Light is made up of tiny particles called-

Anuclear
BNeutron
CPositron
Dphoton

Question 49 of 50

Which instrument is used in submarines to see objects above sea level?

Apyrometer
BEpidiascope
CPereskop
Dodometer

Question 50 of 50

Which colour is dispersion more in rainbow?

APurple
BYellow
CRed
DBlue