A current flows in an a.c. circuit. An e.m.f. E − E0 sin ω t is applied to it. Then the power consumption P is
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Two wires of the same dimensions but resistivities ρ₁ and ρ₂ are connected in series. The equivalent resistivity of the combination is
A potential difference of V is applied at the ends of a copper wire of length l and diameter d. On doubling only d, drift velocity
If intensity of incident light is increased in PEE then which of the following is true
The de Broglie wavelength associated with the particle of mass m moving with velocity v is
The current flowing in a coil of self inductance 0.4 mH is increased by 250 mA in 0.1 s. The e.m.f. induced will be
A capacitor of capacitance 1 μ F is charged to 1KV. The energy stored in the capacitor in joules is
When we touch the terminals of a high voltage capacitor, even after a high voltage has been cut off, then the capacitor has a tendency to
It is easier to roll a barrel than pull it along the road. This statement is
If radius of the earth contracted 2% and its mass remains the same then weight of the body at the earth surface
A black body radiates 20J of energy at 227oC temperature.If temperature of the black body is changed to 727oC, then energy radiated will be
A gas at certain temperature and volume has a pressure equal to 75 cm of Hg. If the mass of the gas is doubled, at the same volume and same temperature, its new pressure will be
The magnetic field at the centre of a circular coil of radius r carrying current I is B₁. The field at the centre of another coil of radius 2 r carrying same current I is B₂. The ratio B₁/B₂ is
When a diamagnetic substance is brought near north or south pole of a bar magnet is
Spherical balls of radius R are falling in a viscous fluid of viscosity η with a velocity v. The retarding viscous force acting on the spherical ball is
A wire of length L and radius a rigidly fixed at one end. On stretching the other end of the wire with a force F, the increase in it length is l. If another wire of same material but of length 2L and radius 2a is stretched with a force 2F, the increase in its length will be
Water drops fall at regular intervals from a tap which is 5 m above the ground. The third drop is leaving the tap at the instant the first drop touches the ground. How far above the ground is the second drop at that instant
A circular road of radius 1000 m has banking angle 45o. The maximum safe speed of a car having mass 2000 kg will be, if the coefficient of friction between tyre and road is 0.5
The distance travelled by an object along the axes are given by x = 2t2, y = t2 - 4t, z = 3t - 5. The initial velocity of the particle is
A body of mass 2 kg is hung on a spring balance mounted vertically in a lift. If the lift descends with an acceleration equal to the acceleration due to gravity 'g', the reading on the spring balance will be
A body is executing simple harmonic motion with an angular frequency 2 rad/s. The velocity of the body at 20 mm displacement, when the amplitude of motion is 60 mm, is
If a spring extends by x on loading, then the energy stored by the spring is (if T is tension in the spring and k is spring constant)
Two plane mirrors are inclined at an angle θ . It is found that a ray incident on one mirror at any angles is rendered parallel to itself after reflection from both the mirrors. The value of θ is
Of two eggs which have identical sizes, shapes and weights, one is raw and the other is half-boiled. The ratio between the moment of inertia of the raw egg and that of the half-boiled egg about a central axis is
A ring of radius r and mass m rotates about an axis passing through its centre and perpendicular to its plane with angular velocity ω. Its kinetic energy is
2 videos|17 docs|85 tests
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2 videos|17 docs|85 tests
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