Electromagnetic Induction — JEE physics STD 12 Science — Question

Assertion : The speedometer of an automobile measure the average speed of the automobile.
Reason : Average velocity is equal to total displacement per total time taken.

Assertion : Inertia is the property by virtue of which the body is unable to change by itself the state of rest only.
Reason : The bodies do not change their state unless acted upon by an unbalanced external force.

Assertion : Work done by a gas in isothermal expansion is more than the work done by the gas in the same expansion, adiabatically.
Reason : Temperature remains constant in isothermal expansion and not in adiabatic expansion.

Assertion : Animals curl into a ball, when they feel very cold.
Reason : Animals by curling their body reduces the surface area.

Assertion : The induced e.m.f. and current will be same in two identical loops of copper and aluminium, when rotated with same speed in the same magnetic field.
Reason : Induced e.m.f. is proportional to rate of change of magnetic field while induced current depends on resistance of wire.

Assertion : A room can be cooled by opening the door of a refrigerator in a closed room.
Reason : Heat flows from lower temperature (refrigerator) to higher temperature (room).

Assertion : Silicon is preferred over germanium for making semiconductor devices.
Reason : The energy gap for germanium is more than the energy gap of silicon.

Assertion : The rate of change of total momentum of a many particle system is proportional to the sum of the internal forces of the system.
Reason : Internal forces can change the kinetic energy but not the momentum of the system.

Assertion : We cannot think of magnetic field configuration with three poles.
Reason : A bar magnet does exert a torque on itself due to its own field.