0

Guest

Courses New

a person 1.6m tall is standing at he centres between two walls three metre high.what is the minimum size of a plane mirror fixed on the wall in front of him, if he is to see full height of the wall behind him?

a person 1.6m tall is standing at he centres between two walls three metre high.what is the
minimum size of a plane mirror fixed on the wall in front of him, if he is to see full height
of the wall behind him?

Grade:12

3 Answers

Nishant Vora IIT Patna
askIITians Faculty 2467 Points
7 years ago
223-2182_Capture.PNG
sayantani bardhan
21 Points
6 years ago
The minimum length of the mirror that is required must not be considered from the ground level. The minimum length required is 1m
Rishi Sharma
askIITians Faculty 646 Points
3 years ago
Dear Student,
Please find below the solution to your problem.

Height of wall h = 3 m
Height of person = 1.6 m
Let us consider height of mirror is h'.
O is the head of the person.
According to figure,
OBC and OB'C' are similar
So,B'C'/BC = O'B'/OB
B'C'/BC = 0.5L / (L+0.5L)
B'C'/BC = 1/3
Now, again
OBA and OB'A' are similar.
O'B'/OB = B'A'/BA
B'A'/BA= 0.5L / (L+0.5L)
B'A'/BA = 1/3
Therefore,
B'C'/BC = B'A'/BA = 1/3
(B'A'+B'C')/(BA+BC) = 1/3
h'/h = 1/3
h' = h/3
h' = 3/3
h' = 1 m
Hence, the minimum size of a plane mirror is 1 m.

Thanks and Regards

Think You Can Provide A Better Answer ?

Other Related Questions on IIT JEE Entrance Exam

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

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