List of top Physics Questions

Consider the junction diode as ideal. The value of current flowing through \(AB\) is :

An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is :

An electric dipole is placed at an angle of $30^{\circ}$ with an electric field intensity $2 \times 10^{5} N / C .$ It experiences a torque equal to $4\, Nm$. The charge on the dipole, if the dipole length is $2\, cm$, is

A rectangular film of liquid is extended from $(4 \, cm \times 2\, cm)$ to $ (5 \, cm \times 4 \, cm)$. If the work done is $3 \times 10^{-4} \, J$, the value of the surface tension of the liquid is -

A $n-p-n$ transistor is connected to common emitter configuration in a given amplifier. A load resistance of $800$ is connected in the collector circuit and the voltage drop across it is $0.8\, V$. If the current amplification factor is $0.96$ and the input resistance of the circuit is $192\,\Omega$, the voltage gain and the power gain of the amplifier will respectively be

A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by $60^{\circ}$ is $W$. Now the torque required to keep the magnet in this new position is

Plancks constant $(h)$, speed of light in vacuum $(c)$ and Newton?s gravitational constant $(G)$ are three fundamental constants. Which of the following combinations of these has the dimension of length?

Which of the following combinations should be selected for better tuning of an $L-C-R$ circuit used for communication ?

When an $\alpha$-particle of mass 'm' moving with velocity 'v' bombards on a heavy nucleus of charge 'Ze', its distance of closest approach from the nucleus depends on m as :

Two non-mixing liquids of densities $\rho$ and $ n\rho (n > 1)$ are put in a container. The height of each liquid is h. A solid cylinder of length L and density d is put in this container. The cylinder floats with its axis vertical and length $ pL (p < 1)$ in the denser liquid. The density d is equal to :

Two identical glass $(\mu_g = 3/2)$ equiconvex lenses of focal length $f$ each are kept in contact. The space between the two lenses is filled with water $(\mu_w = 4/3)$. The focal length of the combination is

Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is at $100^{\circ} C$ , while the other one is at $0^{\circ} C$. If the two bodies are brought into contact, then, assuming no heat loss, the final common temperature is -

The ratio of escape velocity at earth $v_e$ to the escape velocity at a planet $v_p$ whose radius and mean density are twice as that of earth is :

The potential differences across the resistance, capacitance and inductance are $80\, V$, $40\, V$ and $100\, V$ respectively in an $L-C-R$ circuit . The power factor of this circuit is

The potential difference \((V_A - V_B)\) between the points \(A\) and \(B\) in the given figure is

The molecules of a given mass of a gas have r.m.s velocity of $200 \, ms^{-1}$ at $27^{\circ} C$ and $1.0 \times 10^5 \, Nm^{-2}$ pressure. When the temperature and pressure of the gas are respectively, $127^{\circ} C$ and $0.05 \times 10^5 \, Nm^{-2}$, the r.m.s. velocity of its molecules in $ms^{-1}$ is

The magnetic susceptibility is negative for :

The interference pattern is obtained with two coherent light sources of intensity ratio n. In the interference pattern, the ratio $\frac{I_{max} - I_{min}}{I_{max} + I_{min}}$ will be

The charge flowing through a resistance $R$ varies with time t as $ Q = at - bt^2$ , where $a$ and $b$ are positive constants, The total heat produced in $R$ is :

The angle of incidence for a ray of light at a refracting surface of a prism is $45^{\circ}$. The angle of prism is $60^{\circ }$. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index of the material of the prism respectively, are :

In a diffraction pattern due to a single slit of width 'a', the first minimum is observed at an angle $30^{\circ}$ when light of wavelength $5000 \mathring A $ is incident on the slit. The first secondary maximum is observed at an angle of :

Given the value of Rydberg constant is $10^7 \, m^{-1}$, the wave number of the last line of the Balmer series in hydrogen spectrum will be :

From a disc of radius R and mass M, a circular hole of diameter R, whose rim passes through the centre is cut. What is the moment of inertia of the remaining part of the disc about a perpendicular axis, passing through the centre ?

Coefficient of linear expansion of brass and steel rods are $\alpha_1$ and $\alpha_2$. Lengths of brass and steel rods are $ l_1$ and $l_2$ respectively. If $(l_2 - l_1)$ is maintained same at all temperatures, which one of the following relations holds good ?

At what height from the surface of earth the gravitation potential and the value of g are $- 5.4 \times 10^7 \, J \, kg^{-2}$ and $6.0 \, ms^{-2}$ respectively ? Take the radius of earth as $6400 \,km$ :