List of top Physics Questions asked in WBJEE

A hollow cylinder with both sides open generates a frequency $f$ in air. When the cylinder vertically immersed into water by half its length the frequency will be

Two springs are joined and attached to a mass of $16\, kg$. The system is then suspended vertically from a rigid support. The spring constant of the two springs are ${{k}_{1}}$ and ${{k}_{2}}$ respectively. The period of vertical oscillations of the system will be

The equation of a progressive wave can be given by $y=15$ $\sin (660\pi t-0.02\pi x)\,cm.$ The frequency of the wave is

A rocket of mass $100 \,kg$ burns $0.1\, kg$ of fuel per sec. If velocity of exhaust gas is $1 \,km/s^{-1}$, then it lifts with an acceleration of

A beaker of radius $15\, cm$ is filled with a liquid of surface tension $0.75\, N/m$. Force across an imaginary diameter on the surface of the liquid is

Force required to move a mass of $1 \,kg$ at rest on a horizontal rough plane ( $\mu =0.1$ and $g=9.8\,m{{s}^{2}}$ ) is

A shell of mass $10\, kg$ is moving with a velocity of $10\,ms^{-1}$ when it blasts and forms two parts of mass $9 \,kg$ and $1 \,kg$ respectively. If the $1^{st}$ mass is stationary, the velocity of the $2^{nd}$ is

A bullet emerge from a barrel of length $1.2\, m$ with a speed of $640\, ms ^{-1}$. Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is

A battery of e. m. f. $E$ and internal resistance $r$ is connected to an external resistance $R$ the condition for maximum power transfer is

When sound is produced in an aeroplane moving with a velocity of $200 \,m/s$ horizontal its echo is heard after $10\sqrt{5}\,s.$ If velocity of sound in air is the elevation of aircraft is

The binary number $10111$ is equivalent to the decimal number

Two stretched strings have lengths $l$ and $2l$ while tension are $T$ and $4T$ respectively. If they are made of same material the ratio of their frequency is

The equation of transverse wave is given by $y=5\sin 2\pi (\frac{t}{0.04}-\frac{x}{40}),$ where distance is in $\mathrm{cm}$ and time insecond. The wavelength of wave will be

A copper bar of length 1 m and cross-sectional area 10 × 10^-2 m² has its one end maintained at 100^oC by means of 0.4 kW electric heater. What is the temperature of the other end in steady state, given that the thermal conductivity of copper is 400 W/mK?

A small ball is connected to a block by a light string of length L. Both are initially on the ground. There is sufficient friction on the ground to prevent the block from slipping. The ball is projected vertically upwards with a velocity u, where 2gl < u² < 3gl. The centre of mass of the 'block + ball' system is C. Then,

The temperature of an ideal gas is increased from 120 K to 480 K. If at 120 K, the root mean square speed of gas molecules is v, then at 480 K it will be

The light beams of intensities in the ratio of 9 : 1 are allowed to interfere. What will be the ratio of the intensities of maxima and minima ?

The electric potential at a point on the axis of an electric dipole depends upon the distance r (> > a) of the point from centre of the dipole as

The potential energy of a particle varies with distance $x$ from a fixed origin as $\vee =\left(\frac{A\sqrt{x}}{x+B}\right),$ where $A$ and $B$ are constants. The dimensions of AB are

A particle moves in xy plane according to the law x = a sin ωt and y = a(1 - cos ωt), where a and w are constant. The particle traces

In the following common emitter circuit, if β = 100, VCE = 7V, VBE = Negligible and RC = 2 kΩ, then IB is equal to

If the length of the second's hand in a stop-clock is 3 cm, then the angular velocity and linear velocity of the tip is

Experimental investigations show that the intensity of solar radiation is maximum for a wavelength 480 nm in the visible region.Estimate the surface temperature of sun. Given Wein’s constant b = 2.88 × 10^–3 mK.

In the figure, the block B of mass m starts from rest at the top of a wedge W of mass M. All surfaces are without friction. W can slide on the ground. B slides down onto the ground, moves along it with a speed , has an elastic collision with the wall and climbs back onto W. Then,

In the figure, a horizontal force F is applied such that the block remains stationary. Which of the following statements is false?