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Who indirectly determined the mass of the electron by measuring the charge of the electron ?
Resistance of a wire at 20°C is 20 Ω and at 500°C is 60 Ω. At what temperature its resistance is 25 Ω ?
A nichrome wire 50cm long and square millimeter cross-section carries a current of 4A when connected to a 2V battery. The resistivity of nichrome wire in ohm meter is
Two coils are placed close to eachother. The mutual inductance of the pair of coils depends upon
The p.d. across an instrument in an A.C. circuit of frequency f is V and the current flowing through it is I such that V = 5 cos 2π amp. The power dissipated in the instrument 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
The capacity of a condenser with two identical plates separated by a distance 'd' in air is 'C'. If the distance of separation is reduced to d/2, the capacity is
If size of the earth is reduced to half, then no. of days in one year will be
Figure shows two large cylindrical shells having uniform linear charge densities + λ and - λ . Radius of inner aylinder is 'a' and that of outer cylinder is 'b'. A charged particle of mass m , charge q revolves in a circle of radius r. Then its speed 'V' is:
[Neglect gravity and assume the radii of both cylinders to be very small in comparison to their length]
The energy emitted per second by a black body at 27°C is 10 J. If the temperature of the black body is increased to 327°C, the energy emitted per second will be
Vapour is injected at a uniform rate in a closed vessel which was initially evacuated. The pressure in the vessel
At what temperature, the root mean square velocity of a hydrogen molecules is equal to that of an oxygen molecules at 47°C?
The diameter of a copper sphere is 6 cm. It is melted to form a wire of uniform cross-section. If the length of the wire is 36 cm then find the radius of the wire.
A ball of mass m strikes elastically a wall at an angle of 30° with velocity ν. The change in momentum is
If a long hollow copper pipe carries a current, the produced magnetic field will be
In a surface tension experiment with a capillary tube, water rises upto 8 mm. If the same experiment is repeated on an artificial satellite, which is revoling around the earth, water will tise in capillary tube upto a height of
Two solid pieces, one of steel and the other of aluminium when immersed completely in water have equal weights. When the solid pieces are weighed in air
If pressure inside two soap bubbles are 1.01 and 1.02 atm respectively, then the ratio between their volumes is (Take atmospheric pressure = 1 atm)
An incompressible fluid flows steadily through a cylindrical pipe which has radius 2 R at point A and radius R at point B. If velocity at point A is ν, then its velocity at point B is
The potential energy of a molecule on the surface of a liquid compared to one inside the liquid is
Water level rises in a capilary tube, if the angle of contact is
Which of the following affets the elasticity of a substance?
A wire can be broken by applying a load of 200 N.The force required to break another wire of the same length and same material, but double in diameter, is
A body starts from rest. What is the ratio of the distance travelled by the body during the 4th and 3rd second
For a projectile, the ratio of maximum height reached to the square of flight time is (g = 10 ms⁻2)
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