List of top Physics Questions

Charge $Q$ is distributed over a ring, then the force on charge $q$ placed at the centre of the ring will be

The figure shows some of the electric field lines corresponding to an electric field, The figure suggests

The distance between two charges $6\,\mu\,C$ and $15\,\mu\,C$ is $2\,m$. At what point on the line joining the two, the intensity will be zero?

A ball with charge $50 \,e$ is placed at the centre of a hollow spherical shell which has a net charge of $- 50\,e$ . What is the charge on the shells outer surface?

A charged particle is free to move in an electric field. It will travel

An electron moving with the speed $5 \times 10^{6}$ per sec is shooted parallel to the electric field of intensity $1 \times 10^{3} \,N / C$. Field is responsible for the retardation of motion of electron. Now evaluate the distance travelled by the electron before coming to rest for an instant (mass of $e=9 \times 10^{-31} \,kg$, charge $\left.=1.6 \times 10^{-19} \,C \right)$

Let $E_{a}$ be the electric field due to a dipole in its axial plane distant $1$ and let $E _{ q }$ be the field in the equitorial plane distant $1 '$. The relation between $E _{ a }$ and $E _{q}$ is

Two identical conducting balls $A$ and $B$ have positive charges $q_1$ and $q_2$ respectively but $q_1 \ne q_2$ The balls are brought together so that they touch each other and then kept in their original positions. the force between them is

The electric flux for Gaussian surface $A$ that encloses the charged particles in free is (Given $q_1, = - 14 \, n \, C, q_2 = 78.85 \, n \, C, \, q_3 = - 56 \, n \, C) $

Electric field produced by an electron at a point is $E$. What will be electric field produced by $Li^{+++}$ at the same point if it is placed at position of electron ?

Let there be a spherically symmetric charge distribution with charge density varying as $\rho\left(r\right) = \rho_{0} \left(\frac{5}{4}-\frac{r}{R}\right)$ upto $r = R$, and $\rho \left(r\right) = 0$ for $r > R$, where r is the distance from the origin. The electric field at a distance $r\left(r < R\right)$ from the origin is given by

Two charged spherical conductors of radii $ {{R}_{1}} $ and $ {{R}_{2}} $ are connected by a wire. Then the ratio of surface charge densities of the spheres $ {{\sigma }_{1}}/{{\sigma }_{2}} $ is

With the increase of temperature, the surface tension of the liquid

The kinetic energy of an electron, which is accelerated in the potential difference of 100 V, is

Figure shows three spherical and equipotential surfaces A, B and C round a point charge The potential difference $V_A - V_B = V_B - V_C. \, If \, t_1 \, and \, t_2$ be the distances between them, then

A slab of material of dielectric constant $K$ has the same area as the plates of a parallel plate capacitor but has a thickness $\left(\frac{3}{4}\right) d$, where $d$ is the separation of the plates. The ratio of the capacitance $C$ (in the presence of the dielectric) to the capacitance $C_{0}$ (in the absence of the dielectric) is

The effective capacitance between $A$ and $B$ is

An $8\, \mu F$ capacitor is connected across $220\,V, 50 \,Hz $ line. What is the peak value of the charge through capacitor?

0.2 F capacitor is charge to 600 V by a battery, on removing the battery, it is connected with another parallel plate condenser of I F . The potential decreases to

An uncharged capacitor with a solid dielectric is connected to a similar air capacitor charged to a potential of $V_0$. lf the common potential after sharing of charges becomes V, then the dielectric constant of the dielectric must be

Two point-charges $ \pm 10\mu C $ are placed $ 5.00\,mm $ apart, forming an electric dipole. Compute electric field at a point on the axis of the dipole $ 15\,cm $ away from the centre on a line passing through the centre dipole.

The radii of the inner and outer spheres of a condenser are $9\, cm$ and $10\, cm$ respectively. If the dielectric constant of the medium between the two spheres is $6$ and charge on the inner sphere is $18 \times 10^{-9}\, C$, then the potential of inner sphere will be, if the outer sphere is earthed

A number of condensers, each of the capacitance $1 \, \mu F$ and each one of which gets punctured if a potential difference just exceeding $500 \,V$ is applied, are provided. An arrangement suitable for giving capacitance of $2 \, \mu F$ across which $3000 \,V $ may be applied requires at least

Materials suitable for permanent magnet, must have which of the following properties ?

A bar magnet of length $3\, cm$ has points $A$ and $B$ along its axis at distances of $24 \,cm$ and $48\, cm$ on the opposite sides. Ratio of magnetic fields at these points will be