List of top Physics Questions

A coin is made up of Al and weighs $0.75\,g$. It has a square shape and its diagonal measures $17\,mm$. It is electrically neutral and contains equal amounts of positive and negative charges. The magnitude of these charges is ( Atomic mass of Al $= 26.98\,g$)

A conducting sphere of radius $10\,cm$ has unknown charge. If the electric field at a distance $20\,cm$ from the centre of the sphere is $1.2 \times 10^3\, N\, C^{-1}$ and points radially inwards. The net charge on the sphere is

A cup contains $250\,g$ of water. Find the total positive charge present in the cup of water

A dielectric sphere is placed in a uniform electric field directed along the positive y-axis. Which one of the following represents the correct equipotential surface?

A dipole of electric dipole moment p is placed in a uniform electric field of strength E. If $\theta$ is the angle between positive directions of p and E, then the potential energy of the electric dipole is largest when $\theta$ is

A metallic spherical shell has an inner radius $R_1$ and outer radius $R_2$. A charge is placed at the centre of the spherical cavity, the surface charge density on the outer surface is

A point positive charge is brought near an isolated conducting sphere. The electric field is best given by

A positive charge $Q$ is uniformly distributed along a circular ring of radius $R$. A small test charge $q$ is placed at the centre of the ring as shown in figure. Then

A ring of radius R carries a charge Q, uniformly distributed along its circumference. What is the ratio of the electric field strength at a distance R to that at a distance $\frac{R}{\sqrt{2}}$ along the axis?

A rod of length $2.4\, m$ and radius $4.6\, mm$ carries a negative charge of $4.2 \times 10^{-7}\, C$ spread uniformly over it surface. The electric field near the mid-point of the rod, at a point on its surface is

A thin, metallic spherical shell contains a charge Q on it. A point charge q is placed at the centre of the shell and another charge $q_1$ is placed outside it as shown in figure. All the three charges are positive . The force on the charge at the centre is

A uniformly charged conducting sphere of $4.4\,m$ diameter has a surface charge density of $60\, \mu C\, m^{-2}$. The charge on the sphere is

An electron and a proton are situated in a uniform electric field. The ratio of their acceleration will be

A deuteron and an a-particle are placed in an electric field. If $F_1$ and $F_2$ be the forces acting on them and $a_1$ and $a_2$ be their accelerations respectively then, $a_1 = a_2$. Forces will be same in electric field.

Four point charges $q_1, q_2, q_3$ and $q_4$ are as shown in figure. The flux over the shown Gaussian surface depends only on charges $q_1$ and $q_2$. Electric field at all points on Gaussian surface depends only on charges $q_1$ and $q_2$.

In the absence of an external electric field, the dipole moment per unit volume of a polar dielectric is zero. The dipoles of a polar dielectric are randomly oriented.

Charge $q$ is uniformly distributed over a thin half ring of radius $R$. The electric field at the centre of the ring is

Coulomb?? law is true for

Debye is the unit of

Electric field lines provide information about

Electric lines of force about a negative point charge are

Figure below shows a closed surface which intersects a conducting sphere. If a positive charge is placed at the point P, the flux of the electric field through the closed surface

Figure shows electric field lines in which an electric dipole $\vec{p}$ is placed as shown. Which of the following statements is correct?

Five charges $q_1$, $q_2$, $q_3$, $q_4$ and $q_5$ are fixed at their positions as shown in figure. $S$ is Gaussian surface. The Gauss?? law is given by $\oint_{_{_s}}\vec{E}\cdot\vec{ds}=\frac{q}{\varepsilon_{0}}$. Which of the following statements is correct?

Five styrofoam balls are suspended from insulating threads. Several experiments are performed on the balls and the following observations are made - (i) Ball A repels C and attracts B (ii) Ball D attracts B and has no effect on E (iii) A negatively charged rod attracts both A and E. An electrically neutral styrofoam ball gets attracted if placed nearby a charged body due to induced charge. What are the charges, if any, on each ball?