A hollow cylinder has a charge q coulomb within it. It ϕ is the electric flux associated with the curved surface B, the flux linked with the plane surface A will be
In hydrogen atom, radius of the smallest orbit of the electron is a0, the radius of the third orbit is
Which one of the following statements is ‘NOT’ true about the angle of contact of a liquid?
A mass tied to a string is whirled in a horizontal circular path with a constant angular velocity and its angular momentum is L. If the string is now halved, keeping angular velocity same, then the angular momentum will be
In LCR series resonance circuit, choose the wrong statement
A wall is hit elastically and normally by ‘n’ balls per second. All the balls have the same mass ‘m’ and are moving with the same velocity ‘u’. the force exerted by the balls on the wall is
A magnetizing field of 1000 A/m produces a magnetic flux of 2.4 x 10-5 Wb in an iron bar of cross-sectional area 0.3 cm2.The magnetic permeability of the iron bar in SI unit is
For a particular sound wave propagating in air, a path difference between two points is 0.54 m which is equivalent to phase difference of (1.8 π)c. If the velocity of sound wave in air is 330 m/s, the frequency of this wave is
If ‘N’ is the number of turns in a circular coil, the value of its self-inductance varies as
Four identical condensers are connected in parallel and then in series equivalent capacitance in series to that in parallel combination is
Two spheres ‘S1’ and ‘S2’ have same radii but temperatures are ‘T1’ and ‘T2’ respectively. Their emissive power is same and emissivity is in the ratio 1 : 4. Then the ratio ‘T1’ to‘T2’ is
A transistor is used as a common emitter amplifier with a load resistance 2 kΩ. The input resistance is 150 Ω. Base current is changed by 20 μA which results in a change in collector current by 1.5 mA. The voltage gain of the amplifier is
A 4 kg mass and a 1 kg mass are moving with equal energies. The ratio of the magnitude of their linear momenta is
A metal disc of radius ‘R’ rotates with an angular velocity ‘ω’ about an axis perpendicular to its plane passing through its centre in a magnetic field of induction ‘B’ acting perpendicular to the plane of the disc. The induced e.m.f. between the rim and axis of the disc is (magnitude only)
Two coils P and S have a mutual inductance of 5 x 10-3 H. If the current in the coil, P is I = 10 sin (100 πt), then the maximum value of the e.m.f. induced in coil S is
