The correct option is B 5.4 mm
Let us consider the person as the object. So,
Object position (u) = Distance of person from the camera = 25 m
Size of the person = Object size (ho)
= 180 cm = 1.8 m
Since 25 m (Position of person) >> 0.075 m (focus of the lens), rays from the person can be assumed to be parallel.
Image of the person will be formed in the camera film on the focus.
Image position (v) = 0.075 m (Focal length given as 75 mm)
To calculate the image size (height of person on the film hi), we will use the magnification formula.
m = vu = Image size (hi)Object size (ho)
Placing values of v, u and ho ,
⇒0.07525 = hi1.8 m
⇒hi = 0.003 x 1.8 = 0.0054 m
= 5.4 mm
So, the height of the person on the film will be 5.4 mm.