List of top Physics Questions

A particle of charge 10 times that of an electron is revolving in a circular path of radius $0.5 \text{ m}$. If the frequency of rotation is 10 rotations per second, the magnetic field at the centre of the circular path is approximately ($\mu_0 = 4\pi \times 10^{-7} \text{ Hm}^{-1}$)}

Kirchhoff’s first and second laws are respectively based on the conservation of

A battery supplies $0.6 \text{ A}$ current when a $3 \Omega$ resistor is connected with it. When the resistor $3 \Omega$ is replaced by $6 \Omega$, the current is reduced to $0.4 \text{ A}$. Then, the internal resistance of the battery is

A uniform wire of area of cross section $1 \times 10^{-7} m^2$ carries a current of $1.6 \text{ A}$. If the number density of electrons is $5 \times 10^{28} m^{-3}$, the drift velocity of electrons (in $\text{mm s}^{-1}$) is

Two air core capacitors of equal capacitance $C$ are connected in series. If one of them is filled with a dielectric substance of dielectric constant $k$, the effective capacitance becomes

An electric dipole is placed at an angle of $30^\circ$ with an electric field intensity $3 \times 10^5 \text{ NC}^{-1}$ experiences a torque $3 \text{ Nm}$. If the length of dipole is $2 \text{ cm}$, the charge on the dipole is (in milli coloumb)}

A proton travels through a distance of $5\text{ m}$ in the direction of uniform electric field of intensity $4\text{ NC}^{-1}$. The work done on the proton by the electric field is

Two metallic spheres of radii in the ratio 1 : 2 are charged and joined by a connecting wire. The ratio of electric field intensities at the surfaces of the spheres is

In the given wave equation $y=0.05 \sin \frac{2\pi}{\lambda}(x-200t)\text{ m}$, the velocity of the wave (in $\text{ms}^{-1}$) is

When an open pipe is suddenly closed at one end, the frequency of the third harmonic of the closed pipe is found to be $50\text{ Hz}$ more than the fundamental frequency of the open pipe. The fundamental frequency of the open pipe is

The mean free path of moving gas molecules is expressed as $\lambda \propto n^x d^y$ where $n$ is the number of molecules per unit volume and $d$ is the size of the molecules. Then the values of $x$ and $y$ respectively, are

The root mean square velocity of a gas molecule is $100\text{ ms}^{-1}$. The mass of the molecule is increased four times keeping the temperature constant. Then, the root mean square velocity is

When a monoatomic gas at a pressure $P$ is suddenly compressed to $\frac{1}{8}$ of its original volume, the pressure of the gas becomes}

A carnot engine works between the temperatures $327^\circ\text{C}$ and $227^\circ\text{C}$. If the work output of the engine is $1\text{ kJ}$, then the amount of heat absorbed by the engine is

$\gamma_1$ is the ratio of the specific heat capacities of the rigid diatomic gas at constant pressure to that at constant volume and $\gamma_2$ is the corresponding value for a non-rigid diatomic gas molecule with an additional vibrational mode, then the ratio of $\gamma_1$ to $\gamma_2$ is

Bernoulli’s equation holds good for

Two copper wires have the lengths in the ratio $1 : 2$ and their radii are in the ratio $3 : 1$. If they are stretched by the same force, the ratio of the respective longitudinal strains in the two wires is

The escape velocities of two planets $A$ and $B$ are in the ratio $2 : 3$. If the ratio of their radii is $3 : 4$, then the ratio of acceleration due to gravity at the surface of the planet $A$ to that at the surface of the planet $B$ is

The height above the surface of the earth at which the acceleration due to gravity becomes $\frac{g}{9}$ in terms of radius of earth $R$ is ($g$ is acceleration due to gravity at the surface of the earth)}

The torque transmitted by an engine to a rotor in $100 \text{ Nm}$. If the power of the engine is $15 \text{ kW}$, the angular speed of the engine is

If the moment of inertia, rotational kinetic energy and angular momentum of a body are $I$, $E$ and $L$ respectively, then,

In an elastic collision,

The kinetic energy of a body of mass $5 \text{ kg}$ having a linear momentum $4 \text{ kg ms}^{-1}$ is

What will be the maximum speed of a car on a circular road of radius $12 \text{ m}$ if the coefficient of friction between the tyres and the road is $0.3$? $g = 10 \text{ms}^{-2}$}

The linear momentum of a particle as a function of time is given as $p = (3t^2 + 2t + 1)$ kgms$^{-1}$. Then, the force acting on the particle at $t = 3s$ will be}