The first focal length $f_1$ for refraction at a spherical surface is defined as the value of $u$ corresponding to $v=\infty$ (as shown) with refractive indices of two mediums as $n_1$ and $n_2$. The second focal length $f_2$ is defined as value of $v$ for $u=\infty$ (where $R$ is the radius of the curved surface). Choose the correct option(s).

Mark the correct options.

Which of the following quantities related to a lens depend on the wavelength or wavelengths of the incident light?

Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.

A convex lens $(f=0.15 \mathrm{m})$ and a concave mirror (focal length $=0.3 \mathrm{m}$) are placed so that their optical axes $PQ$ and $RS$ are parallel to each other and separated by $0.6 \mathrm{cm}$ as shown. An lateral object $AB$ of height $1.2 \mathrm{cm}$ is placed on the optical axis $PQ$ at a distance of $0.2 \mathrm{m}$ from lens. If $A\text{'}B\text{'}$ is the image after refraction and reflection then choose the correct option(s).

. A point object is placed $30 \mathrm{cm}$ in front of an equiconvex lens of radius of curvature $15 \mathrm{cm}$ and made of glass of refractive index $\frac{3}{2}.$ On placing a convex mirror of radius of curvature $15 \mathrm{cm}$ behind the lens on image side as shown in figure, the final image is found to coincide with the object. The possible distance $\mathrm{x}$ between convex lens and convex mirror is