Size of an image of the object formed by a mirror having a focal length of 26C.M is observed to be reduced to 1/3rd of its size at what distance the object has been placed from the mirror. What is the nature of the image and mirror

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Solution

CASE 1:- m=-1/3(in case of concave mirror)

f= -20 cm
m= -1/3 =-v/u
v=u/3

1/f= 1/v +1/u .

=> -1/20 = 3/u + 1/ u= 4/u

therefore.,, u = -80 cm.

CASE 2:-

M=+1/3 (IN CASE OF CONVEX MIRROR)

f=+20 cm.

m=+1/3 =-v/u

v=-u/3.

i/f=1/v+1/u.
=> 1/20= -3/4 + 1/4 =-2/4

therefore, u= -40 cm.

hope it helps!!

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Size of an image of the object formed by a mirror having a focal length of 26C.M is observed to be reduced to 1/3rd of its size at what distance the object has been placed from the mirror. What is the nature of the image and mirror

CASE 1:- m=-1/3(in case of concave mirror) f= -20 cm m= -1/3 =-v/u v=u/3 1/f= 1/v +1/u . => -1/20 = 3/u + 1/ u= 4/u therefore.,, u = -80 cm. CASE 2:- M=+1/3 (IN CASE OF CONVEX MIRROR) f=+20 cm. m=+1/3 =-v/u v=-u/3. i/f=1/v+1/u. => 1/20= -3/4 + 1/4 =-2/4 therefore, u= -40 cm. hope it helps!!