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

The real image of an object placed on the principal axis of a concave mirror of focal length 12 cm is formed at a point which is 10 cm more distant from the mirror than the object. The magnitude of magnification of the image is:

A
2.0
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
1.5
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
0.67
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
2.5
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B 1.5
Since the mirror is concave, focal length is f=12 cm
Let u be the object distance and v be image distance.

Using mirror formula,
1u+1v=112(i)

Given, image is 10 cm more left than the object. Image distance is:
v=u10(ii)

Substituting (ii) in (i), we get:
1u+1u10=112
u10+u(u10)u=112
Simplifying, we get
u2+14u120=0
u={20 cm, 6 cm}

Object distance cannot be positive.
u=20 cm

Image distance is:
v=u10=30 cm

Magnification is given by:
m=vu
m=(30)20
m=1.5

Magnitude of magnification is:
|m|=1.5

flag
Suggest Corrections
thumbs-up
4
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Lens Formula, Magnification and Power of Lens
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon