Physics-
General
Easy
Question
An e.m.f. of 
is induced in a given coil when the current in it changes at the rate of 
. The self inductance of the coil is
The correct answer is:
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Two concentric coils each of radius equal to 
are placed at right angles to each other. 
and
are the currents flowing in each coil respectively. The magnetic induction in 
at the centre of the coils will be
Two concentric coils each of radius equal to are placed at right angles to each other. and are the currents flowing in each coil respectively. The magnetic induction in at the centre of the coils will be
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A step-up transformer operates on a 
line and supplies a load of 
. The ratio of the primary and secondary windings is 1:25. The current in the primary is
A step-up transformer operates on a line and supplies a load of . The ratio of the primary and secondary windings is 1:25. The current in the primary is
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Find out the e.m.f. produced when the current changes from 0 to 
in 
, given 
Find out the e.m.f. produced when the current changes from 0 to in , given
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A simple pendulum with bob of mass
and conducting wire of length
swings under gravity through an angle 2 
. The earth’s magnetic field component in the direction perpendicular to swing is B. Maximum potential difference induced across the pendulum is
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Physics-General
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A highly conducting ring of radius 
is perpendicular to and concentric with the axis of a long solenoid as shown in fig. The ring has a narrow gap of width 
in its circumference. The solenoid has cross sectional area 
and a uniform internal field of magnitude 
. Now beginning at 
, the solenoid current is steadily increased so that the field magnitude at any time 
is given by 
where 
. Assuming that no charge can flow across the gap, the end of ring which has excess of positive charge and the magnitude of induced e.m.f. in the ring are respectively
A highly conducting ring of radius is perpendicular to and concentric with the axis of a long solenoid as shown in fig. The ring has a narrow gap of width in its circumference. The solenoid has cross sectional area and a uniform internal field of magnitude . Now beginning at , the solenoid current is steadily increased so that the field magnitude at any time is given by where . Assuming that no charge can flow across the gap, the end of ring which has excess of positive charge and the magnitude of induced e.m.f. in the ring are respectively
Physics-General
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In what form is the energy stored in an inductor or
A coil of inductance is carrying a steady current 
. What is the nature of its stored energy
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A coil of inductance is carrying a steady current . What is the nature of its stored energy
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Portion of the wedge shown in figure is rough and BC is smooth. A solid cylinder rolls without slipping from A to B. If AB = BC, then ratio of translational kinetic energy to rotational kinetic energy, when the cylinder reaches point C is -
Portion of the wedge shown in figure is rough and BC is smooth. A solid cylinder rolls without slipping from A to B. If AB = BC, then ratio of translational kinetic energy to rotational kinetic energy, when the cylinder reaches point C is -
Physics-General
Physics-General
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The linear velocity of a particle moving with angular velocity 
=
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=
+
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The linear velocity of a particle moving with angular velocity = at position vector =+ is -
Physics-General
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A circular platform is mounted on a vertical frictionless axle. Its radius is r = 2m and its moment of inertia is I = 200 kg - m2. It is initially at rest. A 70 kg man stands on the edge of the platform and begins to walk along the edge at speed v0 = 1.0 m/s relative to the ground. The angular velocity of the platform is -
A circular platform is mounted on a vertical frictionless axle. Its radius is r = 2m and its moment of inertia is I = 200 kg - m2. It is initially at rest. A 70 kg man stands on the edge of the platform and begins to walk along the edge at speed v0 = 1.0 m/s relative to the ground. The angular velocity of the platform is -
Physics-General
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A particle of mass 1 kg is moving along the line y = x + 2 (here x and y are in metres) with speed 2 m/s. The magnitude of angular momentum of particle about origin is -
A particle of mass 1 kg is moving along the line y = x + 2 (here x and y are in metres) with speed 2 m/s. The magnitude of angular momentum of particle about origin is -
Physics-General
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A disc is rotating with an angular velocity 0. A constant retarding torque is applied on it to stop the disc. The angular velocity becomes 
after n rotations. How many more rotations will it make before coming to rest ?
A disc is rotating with an angular velocity 0. A constant retarding torque is applied on it to stop the disc. The angular velocity becomes after n rotations. How many more rotations will it make before coming to rest ?
Physics-General
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Two rings of same radius (r) and mass (m) are placed such that their centres are at a common point and their planes are perpendicular to each other. The moment of inertia of the system about an axis passing through the centre and perpendicular to plane of one of the ring is -
Two rings of same radius (r) and mass (m) are placed such that their centres are at a common point and their planes are perpendicular to each other. The moment of inertia of the system about an axis passing through the centre and perpendicular to plane of one of the ring is -
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Four particles of mass m1 = 2m, m2 = 4m, m3 = m and m4 are placed at four corners of a square. What should be the value of m4 so that the centre of mass of all the four particles are exactly at the centre of the square ?
Four particles of mass m1 = 2m, m2 = 4m, m3 = m and m4 are placed at four corners of a square. What should be the value of m4 so that the centre of mass of all the four particles are exactly at the centre of the square ?
Physics-General
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A ring of mass 100 kg and diameter 2m is rotating at the rate of 
rpm. Then-
A ring of mass 100 kg and diameter 2m is rotating at the rate of rpm. Then-
Physics-General
Physics-
For particle of a purely rotating body, v = r, so correct relation will be -
For particle of a purely rotating body, v = r, so correct relation will be -
Physics-General
