Identify the figure:

The line passing through $\left(-1, \frac{\pi}{2}\right)$ and perpendicular to $\sqrt{3} \sin \theta + 2 \cos \theta = \frac{4}{r}$ is :

Sunlight of intensity $1.3 ~kW ~m^{-2}$ is incident normally on a thin convex lens of focal length $20 ~cm$. Ignore the energy loss of light due to the lens and assume that the lens aperture size is much smaller than its focal length. The average intensity of light,in $kW m^{-2}$,at a distance $22 ~cm$ from the lens on the other side is.

We have two spheres,one of which is a hollow shell and the other is solid. They have identical masses and moments of inertia about their respective diameters. The ratio of their radii is given by

The frequency of a light ray is $6 \times 10^{14} \ Hz$. Its frequency when it propagates in a medium of refractive index $1.5$ will be:

$A$ particle is executing simple harmonic motion with an amplitude $A$ and time period $T$. The displacement of the particle after $2T$ time from its initial position is