NEET 2010 PYQ Mock Test

The potential difference that must be applied to stop the fastest photo electrons emitted by a nickel surface, having work function $5.01\text{ eV}$, when ultraviolet light of $200\text{ nm}$ falls on it, must be:

The activity of a radioactive sample is measured as $N_0\text{ counts per minute}$ at $t=0$ and $N_0/e\text{ counts per minute}$ at $t=5\text{ minutes}$. The time (in minutes) at which the activity reduces to half its value is:

The energy of a hydrogen atom in the ground state is $-13.6\text{ eV}$. The energy of a ${\text{He}}^{+}$ ion in the first excited state will be:

The mass of a ${}_3^7\text{Li}$ nucleus is $0.042\text{ u}$ less than the sum of the masses of all its nucleons. The binding energy per nucleon of ${}_3^7\text{Li}$ nucleus is nearly:

An alpha nucleus of energy $\frac{1}{2}m{v}^2$ bombards a heavy nuclear target of charge $Ze$. Then the distance of closest approach for the alpha nucleus will be proportional to: