1.
The coil of a heater is cut into two equal halves and only one of them is used in the beater. The ratio of the heat produced by this half of the col to that produced by the original coil is
2.
The force between two parallel wires carrying currents has been used to define
3.
By inserting a soft iron piece into a solenoid, the strength of the magnetic field
4.
Fleming's right hand rule gives
5.
If current in the core decreases, the strength of the magnetic field
6.
By increasing the number of turns in the coil, the strength of the magnetic field
8.
Choose the correct statement:
9.
The unit of induced emf is
11.
The resistance of a conductor is reduced to half its initial value. In doing so the heating effects in the conductor will become
12.
An electric iron draws a current of 4 A when connected to a 220 V mains. Its resistance must be
13.
Ampere rule is used to find the
14.
A compass needle just above a wire in which electrons are moving towards east, will point
15.
The unit of magnetic flux is
16.
The force of repulsion between two parallel wires is f when each one of them carries a certain current /. If the current in each is doubled, the force between them would be
17.
A magnetic field can exert force on a
18.
It is a common notion that the earth's magnetism is due to the
19.
The fact that current is associated with a magnetic field was discovered by
20.
A magnetic field cannot exert any force on a
