If a normal chord at a point $t$ on the parabola $y^2=4ax$ subtends a right angle at the vertex,then $t^2$ equals to

The de-Broglie wavelength of an electron having $80 eV$ energy is nearly ($1 eV = 1.6 \times 10^{-19} J$,Mass of the electron $= 9 \times 10^{-31} kg$,Planck's constant $= 6.6 \times 10^{-34} J-s$) (in $\text{ Å}$)

Freundlich adsorption isotherms for the physical adsorption of a gas at temperatures $T_1$,$T_2$,and $T_3$ are shown in the graph given below. The correct relationship between $T_1$,$T_2$,and $T_3$ is:

The ratio of momenta of an electron and an $\alpha$-particle which are accelerated from rest by a potential difference of $100\, V$ is

In the given circuit,find the equivalent resistance between points $a$ and the combination of $b$ and $c$ (where $b$ and $c$ are connected together).

$A$ bullet of mass $10 ~g$ is fired horizontally with a velocity $1000 ~ms^{-1}$ from a rifle situated at a height $50 ~m$ above the ground. If the bullet reaches the ground with a velocity $500 ~ms^{-1}$,the work done against air resistance in the trajectory of the bullet is : $(g=10 ~ms^{-2})$ (in $~J$)