List of top Physics Questions

A toroidal solenoid with an air core has an average radius of $15 \,cm,$ area of cross-section $12\,cm^2$ and $1200$ turns. Ignoring the field variation across the cross-section of the toroid, the self-inductance of the toroid is

The given four terminal network is part of a larger circuit. The points $A, B, C$ are at the same potential. The potential difference between any one of $A, B $ or $C$ and $D$ is $40\, V$. The potential difference between $A$ and $O$ is

Three solenoid coils of same dimension, same number of turns and same number of layers of winding are taken. Coil 1 with inductance \(L_1\) was wound using an A m wire of resistance \(11\Omega/m\); Coil 2 with inductance \(L_2\) was wound using similar wire but the direction of winding was reversed in each layer; Coil 3 with inductance \(L_3\) was wound using a superconducting wire. The self inductance of coils \(L_1, L_2, L_3\) are

Light travels with a speed of \(2\times 10^{8}\,m/s\) in crown glass of refractive index 1.5. What is the speed of light in 1.8?

A parallel beam of fast moving electrons is incident normally on a narrow slit. A screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statement is correct?

Two identical incandescent light bulbs are connected as shown in the figure. When the circuit is an AC voltage source of frequency \(f\), which of the following observations will be correct?

When a metallic plate swings between the poles of a magnet

When an electrical appliance is switched on, it responds almost immediately, because

A transformer rated at 10 kW is used to connect a 5 kV transmission line to a 240 V circuit. The ratio of turns in the windings of the transformer is

A sample of HCl gas is placed in an electric field \(3\times 10^{4}\,NC^{-1}\). The dipole moment of each HCl molecule is \(6\times 10^{-30}\,Cm\). The maximum torque that can act on a molecule is

Identify the INCORRECT statement regarding a superconducting wire

Three resistances of \(4\Omega\) each are connected as shown in figure. If the point D divides the resistance into two equal halves, the resistance between point A and D will be

The resistance of a metal increases with increasing temperature because

In the absence of applied potential, the electric current flowing through a metallic wire is zero because

A meter bridge is used to determine the resistance of an unknown wire by measuring the balance point length \(l\). If the wire is replaced by another wire of same material but double the length and half the thickness, the balancing point is expected to be

A solid sphere of radius \(R_1\) and volume charge density \(\rho = \frac{\rho_0}{r}\) is enclosed by a hollow sphere of radius \(R_2\) with negative surface charge density \(\sigma\), such that the total charge in the system is zero. \(\rho_0\) is a positive constant and \(r\) is the distance from the centre of the sphere. The ratio \(\frac{R_2}{R_1}\) is

A cylindrical capacitor has charge \(Q\) and length \(L\). If both the charge and length of the capacitor are doubled, by keeping other parameters fixed, the energy stored in the capacitor

If the force exerted by an electric dipole on a charge \(q\) at a distance of 1 m is \(F\), the force at a point 2 m away in the same direction will be

Equal amounts of a metal are converted into cylindrical wires of different lengths (\(L\)) and cross-sectional area (\(A\)). The wire with the maximum resistance is the one, which has

The communication using optical fibers is based on the principle of

The reverse saturation current of p--n diode

In Colpitt oscillator the feedback network consists of

In nature, the electric charge of any system is always equal to

The energy stored in the capacitor as shown in Fig. (a) is \(4.5\times 10^{-6}\) J. If the battery is replaced by another capacitor of 900 pF as shown in Fig. (b), then the total energy of system is