List of practice Questions

A horizontal pipe line carries water in a streamline flow. At a point along the pipe where the cross sectional area is \(10 cm^2\),the water velocity is  \( 1ms^{-1}\) and the pressure is 2000 Pa. What is the pressure at another point where the cross-sectional area is \(5 cm^2\)?

A ring of mass m and radius r is melted and then moulded into a sphere. The moment of inertia of the spheres will be

Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index is 1.7. The focal length of the combination is

Vernalisation is

The time period of oscillation of a magnet in a vibrationmagnetometer is 1.5 sec. The time period of oscillation of another magnet similar in size, shape and mass but having 1/4 magnetic moment than that of the 1 st magnet oscillating at the same place will be

Two particles A and B of equal masses are suspended from two massless springs constants \(k_1,\) and\( k_2,\) respectively. If the maximum velocities, during oscillation, are equal, the ratio of amplitude of A and B is

The length of a second's pendulum at the surface of earth is 1 m. The length of second's pendulum at the surface of moon where g is \(\frac{1}{6}^{th}\) that at earth's surface is

Two containers A and B are aptly filled with water and closed. The volume of A is twice that of B and it contains half theamount of water in B. If both are at the same temperature, the water vapour in the containers will have pressure in the ratio of

If a gas has 'n' degrees of freedom, the ratio of the specific heats \(\gamma\) of the gas is

In P-V diagram shown in figure ABC is a semicircle. The work done in the process ABC is

In the equation \(PV^{\gamma}=\) constant, the value of \(\gamma\) is unity. Then the process is

The ionization energy of hydrogen atom is 13.6 eV. Following Bohr's theory, the energy corresponding to a transition between 3rd and 4th orbit is

The energy of a hydrogen atom in the ground state is \(-13.6 eV.\) The energy of \(He^+\) ion in the first excited state will be

A plane electromagnetic wave travels in free space along x-axis. At a particular temperature point in space, the electric field along y-axis is \(9.3V m^{-1}\). The magnetic induction (B) along z-axis is

Radio waves and visible light in vacuum have

A man is watching two trains, one leaving and the other coming in with equal speeds of 4m/sec. If they sound their whistles, each of frequency 240 Hz, the number of beats heard by the man (velocity of sound in air = 320 m/sec) will be equal to

A band playing music at frequency f is moving towards a wall at a speed \(v_b\). A motorist is following the band with a speed \(v_m\). If v is the speed of sound, the expression for the beat frequency heard by the motorist is

Lenz law is based in principle of conservation of:

Fusion reactions take place at high temperature because

If \(N_0\) is the original mass of the substance of half-life period \( t_{\frac12} = 5\) years, then the amount of substance left after 15 years is

A radioactive element forms its own isotopes after three consecutive disintegrations. The particles emitted are

Which of the following parameters is the same for all hydrogen-like atoms and ions in their ground states?

When hydrogen atom is in its first excited level, it's radius is

A man moving with 2 m/s of 75 kg in west and another man of 50 kg is moving at 4 m/s in north collides in elastically and move together. Find final direction of motion:

If balls collides elastically with fixed wedge and travels horizontally. Find h/H for maximum horizontal range: