Problem 10.2. A convex lens has a focal length of 10 cm. Determine the image distances when an object is placed at the following distances from the lens.
(50 cm, 20 cm, 15 cm, 10 cm and 5 cm).
. A convex lens has a focal length of 10 cm. Determine the image distances when an object is placed at the following distances from the lens..
(50 cm, 20 cm, 15 cm, 10 cm and 5 cm).
Data.
Focal length f=10cm
Object distance =50cm ,20cm,15cm,10cm,5cm,
Image distance q =?
Solution .
Using this lens formula
1/q =1/f - 1/p
1)
1/q=1/10 - 1/50
1/q =50 - 10/500 = 40/500
Q = 500/40 =12.5cm
Q =12.5cm ans
2)
P=20cm
1/q = 1/10 - 1/20
1/q = =20 - 10 /200 =10/200
200/10= 20cm ans
3)
1/q =1/10 -1/15.
= 15- 10/150 =5 /150
Q=150/10
30cm ans
.4)
1/q=1/10 -1/10
10 -10/100= 0/ 100
Q is infinity
5) for p 5cm
1/q =1/10 - 1/5
5 - 10 / 50 =-5/50
50/5 = q = 10cm
