You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Physics

Intensity of Polarised Light

Two circularl...

Question

Two circularly shaped linear polarisers are placed coaxially. The transmission axis of the first polarizer is at $30^{o}$ from the vertical while the second one is at $60^{o}$ , both in the clockwise sense. If an unpolarised beam of light of intensity $I = 20$ $W / m^{2}$ is incident on this pair of polarisers, then the intensities $I_{1}$ and $I_{2}$ transmitted by the first and the second polarisers, respectively, will be close to.

I_{1} = 10.0 W / m^{2}

and

I_{2} = 7.5 W / m^{2}

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

I_{1} = 20 W / m^{2}

and

I_{2} = 15 W / m^{2}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

I_{1} = 10.0 W / m^{2}

and

I_{2} = 8.6 W / m^{2}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

I_{1} = 15.0 W / m^{2}

and

I_{2} = 0.0 W / m^{2}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A $I_{1} = 10.0 W / m^{2}$ and $I_{2} = 7.5 W / m^{2}$
Intensity of unpolarised light $I = 20 W / m^{2}$
Intensity of light passing through first polariser $I_{1} = \frac{I}{2} = \frac{20}{2} = 10 W / m^{2}$
Angle between transmission axis of two poalriser $θ = 60 - 30 = 30^{o}$
Intensity of light passing through second polariser $I_{2} = I_{1} {cos}^{2} θ$
$I_{2} = 10 \times \frac{3}{4} = 7.5 W / m^{2}$

Suggest Corrections

Similar questions

Q. Three circularly shaped linear polarisers are placed coaxially. The transmission axis of the first polariser is at

30^{o}

, the second one is at

60^{o}

and the third at

90^{o}

to the vertical all in the clockwise sense. Each polariser additionally absorbs

10 %

of the light. If a vertically polarised beam of light of intensity

I = 100 W / m^{2}

is incident on this assembly of polarisers, then the final intensity of the transmitted light will be close to:

Q. State clearly how an unpolarised light gets linearly polarised when passed through a polaroid.
(i) Unpolarised light of intensity

I_{0}

is incident on a polaroid

P_{1}

which is kept near another polaroid

P_{2}

whose pass axis is parallel to that of

P_{1}

. How will the intensities of light,

I_{1}

and

I_{2}

, transmitted by the polaroids

P_{1}

and

P_{2}

respectively, change on rotating

P_{1}

without disturbing

P_{2}

?
(ii) Write the relation between the intensities

I_{2}

and

I_{1}

Q. The light from a torch is normally incident on the surface at intensity of illumination

I_{1}

. If the surface is tilted to

45^{\circ}

from initial position, then what will be intensity of illumination

I_{2}

on the surface in terms of

I_{1}

Q. Paragraph : Two plane mirrors kept at an angle

90^{\circ}

, as shown in the figure. It is obvious that

M_{1}

will form an image of point object O, and

M_{2}

will form an image of it. But in practical scenario, a third image is also seen.

The third image formed is :

Q. Unpolarized light with an intensity of

I_{0} = 16 \frac{W}{m^{2}}

is incident on a pair of polarizers. The first polarizer has its transmission axis aligned at

50^{\circ}

from the vertical. The second polarizer has its transmission axis aligned at

20^{\circ}

from the vertical.

What is the intensity of the light when it emerges from the second polarizer?

Join BYJU'S Learning Program