Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.
Close
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

⇐ BackProceed to Checkout ⇒
There are no items in this cart.
Continue Shopping

A thin lens has focal length f, and its aperture has diameter d. It forms an image of intensity I. Now, the central part of the aperture up to diameter d/2 is blocked by an opaque paper The image intensity will change toChoose the correct answer:a. f/2 and I/2b. f and I/4c. 3f /4 and I/2d. f and 3I/4

A thin lens has focal length f, and its aperture has diameter d. It forms an image of intensity I. Now, the central part of the aperture up to diameter d/2 is blocked by an opaque paper The image intensity will change toChoose the correct answer:a. f/2 and I/2b. f and I/4c. 3f /4 and I/2d. f and 3I/4

Grade:12th pass

2 Answers

Arun
25763 Points
3 years ago

Focal length will remains same. 

Intensity is directly proportional to the area of the aperture of the lens receiving  the light. 

Total area of the aperture is,

A = pi * d²/4

Remaining area after covering,

A' = pi *(d²/4  - d²/16) = 3 * pi* d²/16

I/I' = A/A' = 4/3

I' = 3 I/4

Regards

Arun (askIITians forum expert)

Rishi Sharma
askIITians Faculty 646 Points
9 months ago
Dear Student,
Please find below the solution to your problem.

Focal length will remains same.
Intensity is directly proportional to the area of the aperture of the lens receiving the light.
Total area of the aperture is,
A = pi * d²/4
Remaining area after covering,
A' = pi *(d²/4 - d²/16) = 3 * pi* d²/16
I/I' = A/A' = 4/3
I' = 3 I/4

Thanks and Regards

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy

Other Related Questions on Wave Motion

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Register ICAT

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More