List of top Physics Questions

A child swinging on a swing in a sitting position, stands up, then the time period of the swing will:

A heavy small-sized sphere is suspended by a string of length L The sphere rotates uniformly in a horizontal circle with the string making an angle $ \theta $ with the vertical. Then, the time-period of this conical pendulum is

A simple pendulum is oscillating in air with negatively charged bob, now a positively charged conducting plate is placed below the pendulum. The time period of the simple pendulum will

At what distance along the central axis of a uniformly charged plastic disc of radius R is the magnitude of the electric field equal to one-half the magnitude of the field at the centre of the surface of the disc?

A charge $q_1$ exerts some force on a second charge $q_2$. If third charge $q_3$ is brought near, the force of $q_1$ exerted on $q_2$

A charged particle of mass 0.003 g is held stationary in space by placing it in a downward direction of electric field of $ 6 \times 10^4$ N/C. Then the magnitude of charge is

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