real image produced by a concave mirror is found to be 4 times the size of the object .if the distance of the mirror is 20 cm. from the observed ,what is its focal length?
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hello friend...
your answer
image distance (u)= -20 cm
m = 4 = -v/u
So, v= 80 cm
1/f = u+v /uv
1/f = -20+80 /(-20*80) = 60/-1600=3/80
F = -0.0375 cm
hope it helps you...
your answer
image distance (u)= -20 cm
m = 4 = -v/u
So, v= 80 cm
1/f = u+v /uv
1/f = -20+80 /(-20*80) = 60/-1600=3/80
F = -0.0375 cm
hope it helps you...
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