If $X$ is a Poisson variate such that $P(X=1)=P(X=2)$, then $P(X=4)$ is equal to

The velocity at the mean position of a particle executing $S.H.M.$ is $v$. What is the velocity of the particle at a distance equal to half of the amplitude?

Two uniform rods of equal length but different masses are rigidly joined to form an $L$-shaped body,which is then pivoted as shown. If in equilibrium the body is in the shown configuration,the ratio $M/m$ will be:

Which of the following orders is correct for the heat of hydrogenation of these compounds?

$A$ particle moves along a circle of radius $\frac{20}{\pi} \; m$ with constant tangential acceleration. If the velocity of the particle is $80 \; m/s$ at the end of the second revolution after motion has begun,the tangential acceleration is:

Charge passing through a conductor of cross-section area $A=0.3 ~m^2$ is given by $q=3 t^2+5 t+2$ in coulomb,where $t$ is in second. What is the value of drift velocity at $t=2 ~s$ ? (Given,$n=2 \times 10^{25} / m^3$ )