$A$ light wave is incident normally on a glass slab of refractive index $1.5$. If $4\%$ of light gets reflected and the amplitude of the electric field of the incident light is $30\, V/m$,then the amplitude of the electric field for the wave propagating in the glass medium will be.......$ V/m$

$A$ point object is placed at a distance of $25 \, cm$ from a convex lens of focal length $20 \, cm$. If a glass slab of thickness $t$ and refractive index $1.5$ is inserted between the lens and the object,the image is formed at infinity. The thickness $t$ is....$cm$.

The lower half of a vessel of depth $2d \text{ cm}$ is filled with a liquid of refractive index $\mu_1$ and the upper half with a liquid of refractive index $\mu_2$. The apparent depth of the vessel seen perpendicularly is

$A$ convex lens is placed $10\, cm$ from a light source and it forms a sharp image on a screen,kept $10\, cm$ from the lens. Now,a glass block (refractive index $\mu = 1.5$) of $1.5\, cm$ thickness is placed in contact with the light source. To get the sharp image again,the screen is shifted by a distance $d$. Then $d$ is:

$A$ paraxial beam is incident on a glass $(n = 1.5)$ hemisphere of radius $R = 6\, cm$ in air as shown. The distance of the point of convergence $F$ from the plane surface of the hemisphere is......$cm$.

$A$ vessel of depth $2d \ cm$ is half filled with a liquid of refractive index $\mu_1$ and the upper half with a liquid of refractive index $\mu_2$. The apparent depth of the vessel seen perpendicularly is