A car of mass 1000 kg moves on a circular track of radius 40 m. If the coefficient of friction is 1.28. The maximum velocity with which the car can be moved, is
The escape velocity for the earth is 11.2 km/s. The mass of another planet 100 times mass of earth and its radius is 4 times radius of the earth. The escape velocity for the planet is
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Light travels faster in air than that in glass. This is accordance with
The speed of air flow on the upper and lower surfaces of a wing of an aeroplane are v1 and v2 respectively. If A is the cross section area of the wing and p is the density of air, then the upward life is
A body is thrown with a velocity of 9.8 m/s making an angle of 30° with the horizontal. It will hit the ground after a time
A radioactive element 90X238 decays into 83Y222The number of β-particles emitted are
Minimum excitation potential of Bohr’s first orbit in hydrogen atom is
A gas expands 0.25 m3 at constant pressure 103 N/m2, the work done is
The work done in increasing the size of a soap film for 10 cm x 6m to 10 cm x 11cm is 3 x 10-4 J. The surface tension of the film is
A parallel palte condenser is filled with two dielectrics as shown in figure. Area of each pate is A m2 and the separation is d metre.
The dielectric constants are K1 and K2 respectively. Its capacitance in farad will be
A luminous object is placed at a distance of 30 cm from the convex lens of focal length 20 cm. On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature 10 cm be placed in order to have an upright image of the object coincident with it
A battery of emf 10 V and internal resistance of 0.5 ohm is connected across a variable resistance R. The maximum value of R is given by
For a R/Cv gas = 0.67. This gas is made up of cv molecules which are
A point source of light is placed 4 m below the surface of water of refractive index 5/3.
The minimum diameter of a disc which should be placed over the source on the surface of water to cut-off all light coming out of water is
A moving body of mass m and velocity 3 km/h collides with a rest body of mass 2 m and stick to it. Now the combined mass starts to move. What will be the combined velocity?
A transverse wave is represented by the equation
y = y0 sin (2π/λ) – 27c (vt – k)
For what value of X is the particle velocity equal to two times the wave velocity
Ionisation potential of hydrogen atom is 13.6 eV. Hydrogen atom on the ground state rarely excited by monochromatic radiation of photon 12.1 eV. The special line emitted by a hydrogen atom according to Bohr’s theory will be
The internal resistance of a primary cell is 4Ω. It generates a current of 0.2 A in an external resistance of 21Ω The rate at which chemical energy to consumed in providing current is
Two rigid bodies A and B rotate with rotational kinetic energies EA and EBrespectively. The moments of inertia of A and B about the axis of rotation are IA and IB respectively.
If IA = IB and EA = 100 = EB the ratio of 4 angular momentum (LA) of A to the angular momentum (LB) of B is
Progressive waves are represented by the equation
y1 = a sin (ωt – x)
and y2 = b cos (ωt — x)
The phase difference between waves is
Two simple pendulums of length 0.5 m and 20 m respectively are given small linear displacement in one direction at the same time. They will again be in the phase when the pendulum of shorter length has completed x oscillations, where k is
A balloon contains 500 m3 of helium at 27°C and 1 atmosphere pressure. The volume of the helium at —3° C temperature and 0.5 atmosphere pressure will be
220 V, 50 Hz, AC source is connected to an inductance of 0.2 H and a resistance of 20 Ω in series. What is the current in the circuit?
In 0.2 s, the current in a coil increases from 2.0 A to 3.0 A. If inductance of coil is 60 mH, then induced current in external resistanceof 3 Ω will be
Two coherent light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are
A black body has a wavelength of k at temperature 2000 K. Its corresponding wavelength at temperature 3000 K will be
4 videos|8 docs|51 tests
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4 videos|8 docs|51 tests
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