The index of refraction of a glass plate is 1.48 at `theta_(1) = 30.^@C` and varies linearly with
Channel: Doubtnut
Date: 2020-07-26

The index of refraction of a glass plate is 1.48 at `theta_(1) = 30.^@C` and varies linearly with temperature with a coefficient of `2.5 xx 10^(-5).^@C^(-1)`. At 3`0.^@C`, the length of the glass plate is 3 cm. This plate is placed in front of one of the slit n Young's double-slit experiment. If the plate is being heated so that it temperature increases at a rate of `5^(@)C^(-1)` min, the light sources has wavelength `lambda = 589 nm` and the glass plate initially ia at `theta = 30^@C`. The number of fringes that shift on the screen in each minute is nearly (use approximation)