the focal length of a camera lens is 20 cm . how far away from the film must the lens be set in order to photograph an object located at a distance of 100 cm from the lens ?
Answers
Given: The focal length of a camera lens is 20 cm .
To find: How far away from the film must the lens be set in order to photograph an object located at a distance of 100 cm from the lens ?
Solution:
- Now we have given focal length as 20 cm, and u as 100 cm.
- We know the formula:
1/f = 1/v + 1/u
- So putting the values in it, we get:
1/20 = 1/v + 1/100
1/20 - 1/100 = 1/v
100 - 20 / 2000 = 1/v
80 / 2000 = 1/v
4/100 = 1/v
v = 25 cm
Answer:
So the value of v is 25 cm.
Answer:
25 cm
Explanation:
f = 20 cm
u = 100 cm
v = ???
By formula ,
1/f = 1/v + 1/u
=> 1/20 = 1/v + 1/100
=> 1/20 - 1/100 = 1/v
=> 100 - 20 / 2000 = 1/v
=> 80 / 2000 = 1/v
=> 4/100 = 1/v
=> v = 100/4
=> v = 25 cm Ans...