1.
If current in the core decreases, the strength of the magnetic field
2.
The resistance of a conductor is reduced to half its initial value. In doing so the heating effects in the conductor will become
3.
Choose the correct statement:
4.
The fact that current is associated with a magnetic field was discovered by
5.
A compass needle just above a wire in which electrons are moving towards east, will point
7.
A magnetic field can exert force on a
8.
The force between two parallel wires carrying currents has been used to define
9.
An electric iron draws a current of 4 A when connected to a 220 V mains. Its resistance must be
10.
A magnetic field cannot exert any force on a
11.
The unit of magnetic flux is
12.
By inserting a soft iron piece into a solenoid, the strength of the magnetic field
13.
By increasing the number of turns in the coil, the strength of the magnetic field
14.
The unit of induced emf is
15.
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
16.
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
17.
It is a common notion that the earth's magnetism is due to the
19.
Ampere rule is used to find the
20.
Fleming's right hand rule gives
