Chapter 9: Optics – Interference, Diffraction & Polarization (Set-4)

Polarization of light proves that light is

A Longitudinal wave
B Transverse wave
C Scalar wave
D Sound-like wave

Unpolarized light has its electric field

A In a fixed plane
B Randomly oriented in all directions perpendicular to propagation
C Parallel to propagation
D Circular only

Malus’ law gives intensity after a polarizer–analyzer system as

A I = I₀ sinθ
B I = I₀ cosθ
C I = I₀ cos²θ
D I = I₀ / cos²θ

A polarizer converts

A Polarized → unpolarized
B Unpolarized → partially or fully polarized
C Light into heat
D Light into sound

Brewster’s angle is the angle at which

A Reflection is maximum
B Reflection is minimum for perpendicular polarization
C Reflected light is completely plane polarized
D Transmission is zero

Brewster’s angle is given by

A tan iₚ = μ
B sin iₚ = 1/μ
C μ = iₚ
D μ = 1/iₚ

At Brewster angle, the reflected and refracted rays are

A Parallel
B Perpendicular to each other
C Coinciding
D Random

Double refraction (birefringence) occurs in

A Quartz
B Calcite
C Ice
D All of these

Ordinary and extraordinary rays differ in

A Speed inside crystal
B Frequency
C Wavelength outside crystal
D Color

In a uniaxial crystal, the optic axis refers to direction

A Of polarization
B Along which ordinary and extraordinary rays travel same speed
C Of zero refraction
D Of total internal reflection

A Nicol prism works on

A Thin film interference
B Total internal reflection
C Refraction alone
D Diffraction

Nicol prism produces

A Circularly polarized light
B Linearly polarized light
C Unpolarized light
D Elliptical light

A quarter-wave plate introduces a phase difference of

A π/4
B π/2
C π
D

A half-wave plate introduces phase difference of

A π
B π/2
C
D π/4

A quarter-wave plate converts

A Linear → circular or elliptical (if at 45°)
B Circular → linear only
C Unpolarized → polarized
D Circular → sound

Half-wave plate rotates plane of polarization by

A θ
B 2θ (twice the angle between optic axis and incident polarization)
C θ/2
D 90° always

Optical activity is associated with

A Sugar solutions
B Quartz
C Polymers
D All above

Polaroids work based on

A Diffraction
B Dichroism (selective absorption of one polarization component)
C Interference
D Reflection

When unpolarized light passes through a polarizer, transmitted intensity is

A I₀
B I₀/2
C I₀/4
D Zero

Polarization by scattering occurs strongly for

A Very long wavelengths
B Very short wavelengths
C Only microwaves
D Only visible light

Sky appears blue due to

A Diffraction
B Interference
C Polarized scattering of short wavelengths
D Reflection from air

Circular polarization results from

A Two perpendicular linear waves with phase difference π/2 and equal amplitude
B One sine wave only
C Two parallel waves
D One wave of any phase

Elliptical polarization results when

A Amplitudes equal, phase = π/2
B Amplitudes unequal or phase ≠ π/2
C Unpolarized light
D Circularly polarized light only

Brewster angle for air–glass interface (n ≈ 1.5) is

A 30°
B 45°
C ~56°
D ~75°

Polarization cannot occur for

A Transverse waves
B Longitudinal waves
C EM waves
D Light waves

Analyzer is used to

A Produce polarization
B Detect/measure polarization state
C Change wavelength
D Remove intensity

Phase retardation between O-ray and E-ray in a crystal depends on

A Thickness
B Birefringence (nₑ − nₒ)
C Wavelength
D All of these

Optical rotation angle varies

A Directly with length of sample
B Inversely with wavelength
C Directly with concentration
D All of these

Polarization by reflection occurs strongly when

A Incident angle = 45°
B Incident angle = Brewster angle
C Normal incidence
D Incidence = 10°

At Brewster angle, reflected light is polarized

A Perpendicular to plane of incidence
B Parallel to plane of incidence
C Circular
D Elliptical

Quarter-wave plate converts circular polarization back to

A Elliptical only
B Linear (if oriented properly)
C Random
D None

Birefringence produces

A A single refracted ray
B Two rays: O-ray & E-ray
C No rays
D Infinite rays

Dichroism refers to

A Splitting of light into two rays
B Selective absorption of one polarization component
C Interference of polarized waves
D Reflection of two colors

When analyzer is crossed with polarizer, transmitted intensity is ideally

A I₀
B I₀/2
C Zero
D I₀/4

Brewster angle increases when

A Refractive index decreases
B Refractive index increases
C Wavelength increases
D Temperature decreases

Huygens wavelets help explain

A Reflection only
B Refraction only
C Polarization
D Diffraction & interference

Optical path difference between O- and E-ray in a birefringent plate is

A (nₑ − nₒ)t
B nt
C t/λ
D

The fast axis of a wave plate corresponds to

A Higher refractive index
B Lower refractive index
C Equal refractive index
D Changing refractive index

Polarization by double refraction requires

A Transparent isotropic medium
B Birefringent crystal
C Opaque surface
D Metal

Nicol prism is made of

A Calcite
B Quartz
C Sugar
D Polaroid

For circular polarization, the amplitude ratio of two perpendicular components must be

A 1:1
B 2:1
C √2:1
D Zero

When analyzer angle = 45° to polarizer, transmitted intensity is

A I₀
B I₀/2
C I₀/√2
D I₀/4

Brewster angle phenomenon supports

A EM nature of light
B Particle nature
C Gravitational lensing only
D Sound wave propagation

Plane of vibration in a polarized beam is

A Perpendicular to E-field
B Parallel to E-field
C Circular
D Undefined

Optical rotation direction (dextro/levo) depends on

A Crystal type
B Molecular structure
C Concentration
D None

Stress-induced birefringence is used in

A Photoelasticity
B Microscopy only
C Polarizing sunglasses
D Interferometers only

A wave plate’s thickness is chosen so that

A It absorbs light
B It introduces a specific phase retardation
C It causes total reflection
D It scatters light

Light is fully polarized when

A Only one polarization component is present
B Both components equal
C No component
D All components equal

Polaroids reduce glare because

A They remove all light
B They absorb horizontally polarized component predominantly
C They reflect vertical light
D They increase wavelength

Elliptically polarized light can be obtained from

A A quarter-wave plate with unequal amplitudes
B Brewster reflection
C Double-slit
D Zone plates