1.
A compass needle just above a wire in which electrons are moving towards east, will point
2.
The unit of magnetic flux is
3.
The force between two parallel wires carrying currents has been used to define
4.
By inserting a soft iron piece into a solenoid, the strength of the magnetic field
5.
An electric iron draws a current of 4 A when connected to a 220 V mains. Its resistance must be
8.
Choose the correct statement:
9.
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
10.
The unit of induced emf is
11.
If current in the core decreases, the strength of the magnetic field
12.
The fact that current is associated with a magnetic field was discovered by
13.
Fleming's right hand rule gives
14.
A magnetic field can exert force on a
15.
Ampere rule is used to find the
16.
It is a common notion that the earth's magnetism is due to the
17.
The resistance of a conductor is reduced to half its initial value. In doing so the heating effects in the conductor will become
18.
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
19.
A magnetic field cannot exert any force on a
20.
By increasing the number of turns in the coil, the strength of the magnetic field