Question

The magnifying power of a microscope with an objective of 5 mm focal length is 400. The length of its tube is 20 cm. Then the focal length of the eye-piece is

Answer 1

Answer:2.5cm

Explanation:as object distance will be assumed is equal to focal length of objective image distance will be length of microscope approximately. So use this modified formula:

m= L/fo (1+D/fe)

Answer 2

Dear Student,

◆ Answer -

fe = 2.5 cm

● Explanation -

# Given -

M = 400

fo = 5 mm = 5×10^-3 m

L = 20 cm = 0.2 m

D = 25 cm = 0.25 m

# Solution -

Magnifying power of microscope is calculated as -

M = L.D / fo.fe

400 = 0.2 × 0.25 / (5×10^-3 × fe)

fe = 0.2 × 0.25 / (5×10^-3 × 400)

fe = 0.025 m

fe = 2.5 cm

Hence, focal length of eyepiece of microscope is 2.5 cm.

Thanks dear. Hope this helps you...