Aluminium chloride exists as a dimer,$Al_2Cl_6$,in the solid state as well as in solutions of non-polar solvents such as benzene. When dissolved in water,it gives:

The sound waves of wavelengths $5 ~m$ and $6 ~m$ produce $30$ beats in $3 ~s$. The velocity of sound is: (in $~m/s$)

$A$ disk of radius $a/4$ having a uniformly distributed charge $6 \text{ C}$ is placed in the $x-y$ plane with its centre at $(-a/2, 0, 0)$. $A$ rod of length $a$ carrying a uniformly distributed charge $8 \text{ C}$ is placed on the $x$-axis from $x = a/4$ to $x = 5a/4$. Two point charges $-7 \text{ C}$ and $3 \text{ C}$ are placed at $(a/4, -a/4, 0)$ and $(-3a/4, 3a/4, 0)$,respectively. Consider a cubical surface formed by six surfaces $x = \pm a/2, y = \pm a/2, z = \pm a/2$. The electric flux through this cubical surface is

An electric field of $1500\, V/m$ and a magnetic field of $0.40\, Wb/m^2$ act on a moving electron. The minimum uniform speed along a straight line the electron could have is:

In the figure shown,for given values of $R_1$ and $R_2$,the balance point for the jockey is at $40\, cm$ from $A$. When $R_2$ is shunted by a resistance of $10\,\Omega$,the balance point shifts to $50\, cm$. Find $R_1$ and $R_2$ $(AB = 1\, m)$.

Which one of the following elements reduces $NaOH$ to $Na$?