Ray Optics and Optical Instruments Part 1

Given, length of mirror, m=50cm=50×10−2m
Distance of source from mirror, d=60cm
=60×10−2m Distance of man from mirror, dm=1.2m
By using the concept of ray diagram of plane mirror shown belowNow, using the concept of similar triangle,
∆HAl∼△GAE‌ and ‌∆BAl‌∼∆CAE
∴‌‌

AI

AE

=‌

HI

EG

⇒‌‌

0.60

1.8

=‌

0.25

EG

⇒‌EG=0.25×‌

1.8

0.6

=0.25×3=0.75m
‌ As, ‌‌CG=2EG
⇒‌CG=0.75×2=1.50m
‌‌

AI

AE

‌‌=‌

HI

EG

⇒‌‌

0.60

1.8

‌‌=‌

0.25

EG

⇒‌EG‌‌=0.25×‌

1.8

0.6

=0.25×3=0.75m
‌ As, ‌‌CG‌‌=2EG
⇒‌CG=0.75×2=1.50m
Hence, distance between the extreme points, where he can see image of light source in mirror is 150cm.