$A$ light wave is incident normally on a slit of width $24 \times 10^{-5} \ cm$. The angular position of the second dark fringe from the central maxima is $30^{\circ}$. What is the wavelength of light in $\mathring{A}$?

Which part of the world has a high density of organisms?

The ends of a stretched wire of length $L$ are fixed at $x = 0$ and $x = L$. In one experiment,the displacement of the wire is $y_1 = A \sin(\pi x/L) \sin(\omega t)$ and the energy is $E_1$. In another experiment,its displacement is $y_2 = A \sin(2\pi x/L) \sin(2\omega t)$ and the energy is $E_2$. Then:

$A$ ball moving with velocity $2 \, m/s$ collides head-on with another stationary ball of double the mass. If the coefficient of restitution is $0.5$,then their velocities (in $m/s$) after collision will be

Ethyl chloride reacts with sodium ethoxide to form a compound $A$. Which of the following reactions also yields $A$?

Which gas is evolved when $SiO_2$ reacts with sodium carbonate?