Two nuclei have their mass numbers in the ratio of $1:3$. The ratio of their densities would be

What does orthoboric acid contain?

The distribution of relative intensity $I(\lambda )$ of blackbody radiation from a solid object versus the wavelength $\lambda $ is shown in the figure. If the Wien displacement law constant is $2.9 \times 10^{-3}\ mK$,what is the approximate temperature of the object in $K$?

In a $YDSE$,bichromatic light of wavelengths $\lambda_1 = 400\, nm$ and $\lambda_2 = 560\, nm$ are used. The distance between the slits is $d = 0.1\, mm$ and the distance between the plane of the slits and the screen is $D = 1\, m$. The minimum distance between two successive regions of complete darkness is.......$mm$.

Water is being poured at the rate of $36 \ m^3 / min$ into a cylindrical vessel,whose circular base has a radius of $3 \ m$. Then the water level in the cylinder is rising at the rate of:

The enthalpy change $(\Delta H)$ for the reaction $N_{2(g)} + 3H_{2(g)} \to 2NH_{3(g)}$ is $-92.38 \ kJ$ at $298 \ K$. The internal energy change $\Delta U$ at $298 \ K$ is $...... \ kJ$.