$A$ motor-car tyre has a pressure of $2\, atm$ at $27\,^{\circ}C$. It suddenly bursts. If $\gamma = \frac{C_p}{C_v} = 1.4$ for air,find the resulting temperature. (Given $4^{1/7} = 1.219$)

Starting with a sample of pure $^{66}Cu$,$\frac{7}{8}$ of it decays into $Zn$ in $15 \ min$. The corresponding half-life is .......... $min$.

Two cylinders $A$ and $B$ fitted with pistons contain equal amounts of an ideal diatomic gas at $300\,K$. The piston of $A$ is free to move,while that of $B$ is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $30\,K$,then the rise in temperature of the gas in $B$ is .... $K$.

$A$ value of $n$ such that $\left(\frac{\sqrt{3}}{2}+\frac{i}{2}\right)^n=1$ is

Cardiac muscles contract:

The correct stability order for the following carbocations is: