CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

A bright point S is on the principal optical axis of a concave mirror of radius R=40cm at d=30cm from its pole. At what distance (in cm) in front of the concave mirror should a plane mirror be placed so that after two reflections, the rays converge back at point S.

A
30
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
35
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
40
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
45
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is C 45
Given: R=40cm, object distance u=30cm
For the mirror 1
(1/v) + (1/u) = (1/f)
y = -30
(1/v) – (1/30) = - (1/20)
f = -20 (1/v) = (1/30) – (1/20)
v = -60 cm so the distanxe from the object is x = 15cm
therefore, distance between two mirrors = 30+15=45 cm .

1639181_1759942_ans_2c91cfd271ec4737953531979fee7e56.PNG

flag
Suggest Corrections
thumbs-up
0
similar_icon
Similar questions
View More
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Fringe Width
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon