Polarization MCQs

Question 1

Two Polaroids with their axes at 90^circ ('crossed') transmit:

Accepted Answer

no light

Answer

all the light

Answer

half the light

Answer

only red light

Question 2

Light reflected from a lake surface is:

Accepted Answer

partially polarized

Answer

converted into sound

Answer

longitudinal

Answer

completely unpolarized

Question 3

Plane-polarized light of intensity 100 W/m^2 is reduced to 25 W/m^2 by a polarizer. The angle between the polarization plane and the polarizer's axis is:

Accepted Answer

60^circ

Answer

75.5^circ

Answer

30^circ

Answer

63^circ

Question 4

In photoelastic stress analysis, a transparent plastic model is viewed between crossed polarizers to:

Accepted Answer

show coloured fringe patterns revealing stress

Answer

check its electric charge

Answer

measure the model's mass

Answer

find its temperature

Question 5

LCD screens use polarizers because:

Accepted Answer

liquid crystals control the light by rotating its plane of polarization

Answer

they focus light

Answer

they need sound waves

Answer

they emit polarized sound

Question 6

Rotating a polarizing filter while photographing the sky makes the sky:

Accepted Answer

darker or lighter depending on the angle

Answer

stay exactly the same

Answer

disappear

Answer

change to red

Question 7

Plane-polarized light of intensity 60 W/m^2 falls on a polarizing filter whose axis is at 37^circ to the plane of polarization. The transmitted intensity is:

Accepted Answer

38.3 W/m^2

Answer

76.5 W/m^2

Answer

19.1 W/m^2

Answer

383 W/m^2

Question 8

Plane-polarized light of intensity 200 W/m^2 falls on a polarizing filter whose axis is at 90^circ to the plane of polarization. The transmitted intensity is:

Accepted Answer

0 W/m^2

Answer

100 W/m^2

Answer

200 W/m^2

Answer

50 W/m^2

Question 9

A plane-polarized wave is one in which the vibrations are:

Accepted Answer

in one plane only

Answer

in all planes

Answer

along the direction of travel

Answer

circular only

Question 10

At theta = 45^circ, the fraction of plane-polarized light transmitted is:

Accepted Answer

12

Answer

14

Answer

1

Answer

1 2

Question 11

A longitudinal wave passes through a Polaroid filter:

Accepted Answer

unchanged in polarization (it can't be polarized)

Answer

completely blocked

Answer

converted to transverse

Answer

plane-polarized

Question 12

A polarizing filter darkens the sky most when the camera points at about:

Accepted Answer

90^circ to the Sun

Answer

directly away from the Sun

Answer

directly at the Sun

Answer

at the horizon under the Sun

Question 13

Polarization is possible only for:

Accepted Answer

transverse waves

Answer

sound waves

Answer

all waves

Answer

longitudinal waves

Question 14

Which of these can be polarized?

Accepted Answer

radio waves

Answer

sound waves in air

Answer

ultrasound in water

Answer

seismic P-waves

Question 15

3-D cinema glasses use:

Accepted Answer

differently polarized lenses so each eye sees a different image

Answer

magnifying lenses

Answer

coloured lenses only

Answer

sound filters

Question 16

Unpolarized light consists of vibrations:

Accepted Answer

in all directions perpendicular to the direction of travel

Answer

along the direction of travel

Answer

none at all

Answer

in one plane only

Question 17

Photographers use a polarizing filter on a camera to:

Accepted Answer

reduce glare and reflections and darken blue skies

Answer

increase the brightness of reflections

Answer

change the colour of objects

Answer

magnify distant objects

Question 18

Polaroid sunglasses reduce glare because:

Accepted Answer

they block the polarized light reflected from horizontal surfaces

Answer

they reflect sunlight

Answer

they magnify the image

Answer

they absorb all light

Question 19

Engineers use photoelastic models to:

Accepted Answer

find weak points in designs such as bridges, hooks and gears

Answer

make models heavier

Answer

measure sound levels

Answer

test electrical circuits

Question 20

Malus's law involves cos^2theta because:

Accepted Answer

the filter passes the amplitude component Acostheta, and intensity ∝ amplitude^2

Answer

light travels at an angle

Answer

the filter absorbs half

Answer

intensity is proportional to amplitude

Question 21

Plane-polarized light of intensity 50 W/m^2 falls on a polarizing filter whose axis is at 0^circ to the plane of polarization. The transmitted intensity is:

Accepted Answer

50 W/m^2

Answer

500 W/m^2

Answer

100 W/m^2

Answer

25 W/m^2

Question 22

Blue skylight at 90^circ to the Sun is:

Accepted Answer

strongly polarized

Answer

infrared only

Answer

longitudinal

Answer

completely unpolarized

Question 23

For light, the direction of polarization is usually taken as the direction of vibration of the:

Accepted Answer

electric field

Answer

magnetic field

Answer

wave's motion

Answer

photon's spin axis

Question 24

Sound waves in air cannot be polarized because they are:

Accepted Answer

longitudinal

Answer

electromagnetic

Answer

too fast

Answer

transverse

Question 25

Polarization distinguishes transverse waves from longitudinal waves because:

Accepted Answer

only transverse waves have a vibration direction perpendicular to travel that can be selected

Answer

transverse waves are always light

Answer

longitudinal waves have no frequency

Answer

longitudinal waves are slower

Polarization MCQs — Physics

1. Two Polaroids with their axes at 90^circ ('crossed') transmit:

2. Light reflected from a lake surface is:

3. Plane-polarized light of intensity 100 W/m^2 is reduced to 25 W/m^2 by a polarizer. The angle between the polarization plane and the polarizer's axis is:

4. In photoelastic stress analysis, a transparent plastic model is viewed between crossed polarizers to:

5. LCD screens use polarizers because:

6. Rotating a polarizing filter while photographing the sky makes the sky:

7. Plane-polarized light of intensity 60 W/m^2 falls on a polarizing filter whose axis is at 37^circ to the plane of polarization. The transmitted intensity is:

8. Plane-polarized light of intensity 200 W/m^2 falls on a polarizing filter whose axis is at 90^circ to the plane of polarization. The transmitted intensity is:

9. A plane-polarized wave is one in which the vibrations are:

10. At theta = 45^circ, the fraction of plane-polarized light transmitted is:

11. A longitudinal wave passes through a Polaroid filter:

12. A polarizing filter darkens the sky most when the camera points at about:

13. Polarization is possible only for:

14. Which of these can be polarized?

15. 3-D cinema glasses use:

16. Unpolarized light consists of vibrations:

17. Photographers use a polarizing filter on a camera to:

18. Polaroid sunglasses reduce glare because:

19. Engineers use photoelastic models to:

20. Malus's law involves cos^2theta because:

21. Plane-polarized light of intensity 50 W/m^2 falls on a polarizing filter whose axis is at 0^circ to the plane of polarization. The transmitted intensity is:

22. Blue skylight at 90^circ to the Sun is:

23. For light, the direction of polarization is usually taken as the direction of vibration of the:

24. Sound waves in air cannot be polarized because they are:

25. Polarization distinguishes transverse waves from longitudinal waves because:

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