Question

For refraction at a curved surface identify the wrong statement with accordnce to the curved surface formula.

• A. ${\mu }_2$ is the refractive index of the medium, at which the refraction takes place.
• B. ${\mu }_1$ is the refractive index of the medium, from where the light is incident on the surface.
• C. R is the radius of curvature of the refractive surface.
• D. R is always positive.

Answer 1

The correct option is D R is always positive.

The curved surface formula is,

$\frac{{\mu }_2}{v}-\frac{{\mu }_1}{u}=\frac{{\mu }_2-{\mu }_1}{R}$

where ${\mu }_2$ is the refractive index of the medium in which the refraction takes place and ${\mu }_1$ is the refractive index of the medium, from where the light is incident on the surface and
R is the radius curvature of the surface.

R can be positive or negative depending on the refracting surface. If the refracting surface is concave the value is negative and if it is convex the value if positive.