How for
should
an Object be from the
pole of a concave mirror of Focal length 20 cm to
find real Image whose
size in
1/5 of the size of the object
Answers
Answered by
1
Answer:120
Explanation:
given,
Focal length(f)= -20
Magnification(m)= -1/5
Object distance(u)= ?
We know
m=-v/u
-1/5=-v/u
-u=-5v
u=5v. ...........i
Now
1/f=1/v+1/u
-1/20=1/v+1/5v
-1/20=5+1/5v
-1/20=6/5v
-5v=120
-v=120/5
Therefore v=-24
Now putting the value of v in .....i,we get. u=5*-24=-120 cm
Thus the object should be placed at 120 cm in front of the mirror
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