a convex lens forms a real image 4 times magnified at the distance of 60 cm from the lens calculate the focal length and the power of the lens
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Answered by
8
m = -4
v÷u =-4
60÷u =-4
u =-15 cm
1÷v- 1÷u =1 ÷f
1÷60 - 1÷-15 =1÷f
1÷60+1÷15 =1÷f
(1+4)÷60 =1÷f
5÷60 = 1 ÷ f
f=12cm
f=0.12m
p = 1÷f D
p =1 ÷ 0.12
p= 8.33D
p=8.33D. f =12 cm
v÷u =-4
60÷u =-4
u =-15 cm
1÷v- 1÷u =1 ÷f
1÷60 - 1÷-15 =1÷f
1÷60+1÷15 =1÷f
(1+4)÷60 =1÷f
5÷60 = 1 ÷ f
f=12cm
f=0.12m
p = 1÷f D
p =1 ÷ 0.12
p= 8.33D
p=8.33D. f =12 cm
Answered by
1
Answer:
Explanation:
Convex lens
m= -4 ( image is real )
v= 60 cm
m
u
v = =− 4 u
v
4 & = − 4
60 =−
=− 15 cm
From the lens formula,
f
1
v u
1 1 = − 60
1
15
1 = − −
60
1 4 = +
60
5 = 12
1 =
Focal length, f = 12 cm 100
12 = m
The power of the lens, P f in m
1 = ^ h
m
1
100
= 12 D 12
100 =
= 8 33 . D
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