List of top Physics Questions

Kirchhoff's first and second laws of electrical circuits are consequences of

Two cells, having the same e.m.f. are connected in series through an external resistance R. Cells have internal resistances $r_1$ and $r_2\, (r_1 >\, r_2)$ respectively. When the circuit is closed, the potential difference across the first cell is zero. The value of R is :-

What is SI unit of electric field intensity?

The radioactivity of a sample is x at time $t_1$ and is y at time $t_2$. If the mean life of the specimen is $\tau$, the number of atoms that have disintegrated in the time interval $(t_2 - t_1)$ is

Emission of light stops as the incident light is cut-off in

You are given n resistors, each of resistance r. They are first combined to get minimum possible resistance, then they are connected to get the maximum possible resistance. The ratio between rrurnmum to maximum resistance is

A critical angle for a medium is $60^\circ.$ Then the refractive index of the medium will be

In a transistor amplifier, the two AC current gains $\alpha $ and $ \beta $ are defined as $\alpha=\frac{\partial I_C}{\partial I_E} $ and $ \beta =\frac{\partial I_C}{\partial I_B}$ the relation between $\alpha$ and $\beta$ is

If the magnetic flux is represented in weber, then the unit of magnetic induction will be

If the electric current in a lamp decreases by $5 \%,$ then the power output decreases by

The electric potential at the surface of an atomic nucleus (Z = 50) of radius $ 9 \times 10^{ - 15} \, m$ is

As electric dipole placed in a non-uniform electric field in such a way that angle between $p$ and $E$ is not $0^\circ$ or $ 180^\circ $, so it experiences

Two capacitors of capacitance $C_1$ and $C_2$, are connected in parallel. If a charge Q is given to the combination, the charge gets shared. The ratio of the charge on the capacitor $C_1$ to the charge on the capacitor $C_2$ is

A block of mass $ 2\,kg $ rests on a horizontal surface. If a horizontal force of $ 5\,N $ is applied on the block the frictional force on, it is $ (\mu _{k}=0.4,\,\mu _{s}=0.5) $

Electromagnetic waves can be deflected by

A bar magnet is held at right angles to a uniform magnetic field. The couple acting on the magnet is to be halved by rotating it from this position. The angle of rotation is

A circular coil of radius 40 mm consists of 250 turns of wire in which the current is 20mA. The magnetic field in the center of the coil is $\mu =4\pi?10^{-7}Hm^{-1}$

The velocity $v$ of a particle at time $t$ is given by $v=at+\frac{b}{t+c}$ , where $a$, $b$ and $c$ are constants. The dimensions of $a$, $b$ and $c$ are, respectively,

A current of 5A is passing through a metallic wire of cross-sectional area $4\times10^{-6}m^2$ If the density of the charge carriers in the wire is 5 ? $10^{26}m^{-3}$, the drift speed of the electrons will be [e = 1.602 ? $10^{-19}C$]

Three resistances of values 2$\Omega$, 3$\Omega$ and 6$\Omega$ are to be connected to produce an effective resistance of 4$\Omega$ . This can be done by connecting

A rectangular vessel when full of water, takes $10$ minutes to be emptied through an orifice in its bottom. How much time will it take to be emptied when half filled with water ?

A solenoid $1.5\, m$ long and $0.4\, cm$ in diameter possesses $10$ turns per cm length. A current of $5\, A$ flows through it. The magnetic field at the axis inside the solenoid is

An unpolarised beam of intensity $I_0$ is incident on a pair of nicols making an angle of $60^\circ$ with each other. The intensity of light emerging from the pair is

If $\lambda_{1}$ and $\lambda_{2}$ are the wavelengths of the first members of the Lyman and Paschen series respectively, then $\lambda_{1}: \lambda_{2}$ is

The series combination of two capacitors shown in figure is connected across 1000V. The magnitude of the charges on the capacitors will be