The number of turns in the primary and the secondary turns of a transformer are 1000 and 3000 respectively. If 80 volts A.C. is supplied to the primary coil of the transformer, then the potential difference/turn of the secondary coil would be
A shell initially at rest explodes into two pieces of equal mass. The two pieces will
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Three cells each of e.m.f. 1.5 V and internal resistance 1 Ω are connected in parallel. What would be the e.m.f. of the combination ?
Electron microscope use electron for their which property
The speed of electrons in a cathode ray beam which remains undeflected, in Thomson's experiment, under the simultaneous action of a magnetic field of 2 X 10−3 wbm−2 and that of an electric field of 3 . 4 X 10 4 V m − 1 is
The charge deposited on 4 μ F capacitor in the circuit is
A photocell stops emission if it is maintained at 2V negative potential. The energy of most energetic photoelectron is
If a radiation of energy E falls normally on a perfectly reflecting surface, then the momentum transferred to the surface is
If momentum of a particle is doubled, then its de-Broglie's wavelength will
The north pole of a long horizontal bar magnet is being brought closer to a vertical conducting plane, along the perpendicular direction. The induced current in the conducting plane is
The energy stored in coil carrying current I s U. If current is halved, then energy stored in the coil will be
A coil of inductances 300mH and resistance 2 Ω is connected to a source of voltage 2V. The current reaches half of its steady state value in
A point charge q is placed at the centre of a skeleton cube made of thin non-conducting wire. The electric flux passing through one face of the cube is
A parallel plate capacitor is first charged and then a dielectric slab is introduced between the plates. The quantity that remains unchanged is
Two bodies of mass m₁ and m₂ have equal kinetic energies. If p₁ and p₂ are their respective momentum, then ratio p₁ : p₂ is equal to
A long spring is stretched by 2 cm, its potential energy is U. If the spring is stretched by 10 cm, the potential energy stored in it will be
The lengths and radii of two rods made of same material are in the ratios 1:2 and 2:3 respectively. If the temperature difference between the ends for the two rods be the same, then in the steady state, the amount of heat flowing per second through them will be in the ratio
A 100 W, 200 V bulb is connected to a 160 volt supply. The actual power would be
When a material is placed in magnetic field 'B'. Magnetic moment proportional to 'B' but opposite in direction is induced. The material is
A thin rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely in the same field. If its period of oscillation is T ′ the ratio T ′ T is
The ratio of tangential stress to the shearing strain is called
A wagon 1000 kg is moving with a velocity 50 km/h on smooth horizontal rails. A mass of 250 kg is dropped into it. The velocity with which it moves now is
The particle having a major role in binding the nucleus is-
Average value of K.E. and P.E. over entire time period is
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): We use a thick wire in the secondary of a step down transformer to reduce the production of heat.
Reason(R): When the plane of the armature is parallel to the line of force of magnetic field, the magnitude of the induced emf is maximum.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): A graph between the absolute temperature (T) of a gas and the square of speed of sound (v2) will bea parabola.
Reason(R): symbols have their usual meaning .
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Frequency of note emitted by an organ pipe will decrease with rise in temperature.
Reason(R): Frequency =
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): A uniform thin rod of length L is hinged about one of its end is free to rotate about the hinge without friction. Neglect the effect of gravity. A force F is applied at a distance x from the hinge on the rod such that force is always perpendicular to the rod. As the value of x is increased from zero to L, the component of reaction by hinge on the rod perpendicular to length of rod increases.
Reason(R) : Under the conditions given in statement 1 as x is increased from zero to L, the angular acceleration of rod increases.
3 videos|44 docs|66 tests
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3 videos|44 docs|66 tests
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