Diffusion current in a $p$-$n$ junction is greater than the drift current in magnitude when:

To the free end of a spring hanging from a rigid support,a block of mass $m$ is hung and slowly allowed to come to its equilibrium position. Then the stretching in the spring is $d$. If the same block is attached to the same spring and allowed to fall suddenly,the amount of stretching is: (force constant,$k$)

The rate of disintegration of a fixed quantity of a radioactive element can be increased by

The number of solutions of the system of equations $2x + y - z = 7$,$x - 3y + 2z = 1$,and $x + 4y - 3z = 5$ is:

The equilibrium constant at $298 \ K$ for the reaction $A + B \rightleftharpoons C + D$ is $100$. If the initial concentrations of all the four species were $1 \ M$ each,then the equilibrium concentration of $D$ (in $mol \ L^{-1}$) will be

Which of the following is a co-enzyme?