Changing the f-number of a camera lens by 4x will change the light intensity admitted to the film by what factor? a) 16 b) 0.0625 c) 2 d) 0.25 e) 4

option B is correct

factor is 0.0625

Explanation:

Given data

camera lens = 4X

to find out

find factor

solution

we know Inverse square law that is the intensity is inversely proportional to the square of the distance from the source i.e f

so we say intensity ( I )  ∝ 1 / f

so I1 / I2 = f2² / f1²

so I2 will be

I2 =   f2² / f1² × I1

I2 =  1 / 4² × I1

I2 = 0.0625

so option B is correct

factor is 0.0625

the ima (higher than 1m) will be greater than the ima with the height of 1m.