List of practice Questions

The number density of electrons and holes in pure silicon at $27 ^{\circ}C$ are equal and its value is $2.0 \times 10^{16}\, m^{-3}$. On doping with indium the hole density increases to $4.5 \times 10^{22}\, m^{-3}$, the electron density in doped silicon is

A solid sphere of volume $V$ and density $\rho$ floats at the interface of two immiscible liquids of densities $\rho_1$ and $\rho_2$ respectively. If $\rho_1$ < $\rho_2$ < $\rho_3$, then the ratio of volume of the parts of the sphere in upper and lower liquid is

Which one is a neem product used as insect repellent?

A ray incident at a point at an angle of incidence of $60^{\circ}$ enters a glass sphere of refractive index $\sqrt{3}$ and is reflected and refracted at the farther surface of the sphere. The angle between the reflected and refracted rays at this surface is

Arrangement of sex chromosomes in Klinefelter's syndrome is

The stability of the following alkali metal chlorides follows the order

Electric potential is :

Electric intensity is equal to :

Let \(f(x)=αsin^{2}3x.\) If \(f'(π/12)=-3\) ,then the value of \(α \) is_____.

A solution of $MgCl_2$ in water has pH

Electric field on the axis of a small electric dipole at a distance $r$ is $\overrightarrow{ E }_{1}$ and $\overrightarrow{ E }_{2}$ at a distance $2 r$ on a line of perpendicular bisector. Then

Electronic configuration of an element 'X' having atomic number 24 is

The nucleus of an atom consists of

Which one is a broad spectrum antibiotic ?

Which one is involved in $Z$-scheme of photosynthesis?

The noble gas which shows abnormal behaviour in the liquid state is

Which one is not a pollutant normally ?

The noble gas which is radioactive is

Which one is the correct summary equation of nitrogen fixation ?

The coefficient of $x_n$ in the expansion of $\frac{e^{7x}+e^x}{e^{3x}}$ is

Which one of the following alcoholic drinks is produced without distillation ?

Effective nuclear charge $\left(Z_{eff} \right)$ for a nucleus of an atom is defined as

Which one is the correct summary equation of photosynthesis?