$A$ black body at a temperature of $227^{\circ}C$ radiates heat energy at the rate of $5 \ cal/cm^2-sec$. At a temperature of $727^{\circ}C$,the rate of heat radiated per unit area in $cal/cm^2-sec$ will be:

In a reaction of $C_6H_5Y$,the major product $(> 60\%)$ is $m$-isomer,so the group $Y$ is:

$A$ stone of mass $m$ is tied to a string and is moved in a vertical circle of radius $r$ making $n$ revolutions per minute. The total tension in the string when the stone is at its lowest point is

If a ladder weighing $250 \ N$ is placed against a smooth vertical wall and the coefficient of friction between the ladder and the floor is $0.3$,what is the maximum force of friction available at the point of contact between the ladder and the floor?

Assign $A, B, C, D$ from the given type of reaction.
$4KCN + Fe(CN)_2 \downarrow \longrightarrow K_4[Fe(CN)_6]$

The $r.m.s.$ value of an $AC$ of $50\,Hz$ is $10\,A$. The time taken by the alternating current to reach from zero to maximum value and the peak value of current will be: