Data Entry - Physics

$\cos \left[\cos ^{-1}\left(-\frac{1}{7}\right)+\sin ^{-1}\left(-\frac{1}{7}\right)\right]$ is equal to

The potential difference between the plates of a parallel plate capacitor is changing at the rate of $10^6\, V/s$. If the capacitance is $2\,\mu F$,the displacement current in the dielectric of the capacitor will be.....$A$

An achromatic combination of lenses produces

In the figure shown,the velocities of different blocks are given. The velocity of $C$ is $.........\,m/s$.

The existence of a substance in more than one solid modification is known as: