1.
By inserting a soft iron piece into a solenoid, the strength of the magnetic field
2.
The unit of induced emf is
3.
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
4.
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
6.
Ampere rule is used to find the
7.
An electric iron draws a current of 4 A when connected to a 220 V mains. Its resistance must be
8.
It is a common notion that the earth's magnetism is due to the
9.
Fleming's right hand rule gives
10.
The unit of magnetic flux is
11.
If current in the core decreases, the strength of the magnetic field
12.
A magnetic field cannot exert any force on a
13.
By increasing the number of turns in the coil, the strength of the magnetic field
15.
Choose the correct statement:
16.
The resistance of a conductor is reduced to half its initial value. In doing so the heating effects in the conductor will become
17.
The force between two parallel wires carrying currents has been used to define
18.
The fact that current is associated with a magnetic field was discovered by
19.
A magnetic field can exert force on a
20.
A compass needle just above a wire in which electrons are moving towards east, will point
