Question

In a biprism experiment, when a convex lens was placed between the biprism and eyepiece at a distance of 30 cm from the slit, the virtual images of the slits are found to be separated by 7 mm. If the distance between the slit and biprism is 10 cm and between the biprism and eyepiece is 80cm, find the linear magnification of the image.

Answer 1

Given : D = 10 + 80 = 90 cm, d = 30 cm, d₁ = 90 - 30 = 60 cm

To find : Linear magnification (m)

Formula : Linear magnification ${\displaystyle m=\frac{d_1}{d}=\frac{\text{v}}{u}}$

Calculation : From formula,

${\displaystyle \frac{d_1}{d}=\frac{\text{v}}{u}=\frac{60}{30}}$

∴ m = 2
The linear magnification of the image is 2.