SECTION - A
1. Define power and its SI unit.
2. A current flows through a horizontal wire in west to east direction. What is the direction
of magnetic field at a point below it when viewed from east end?
3. How is the direction of magnetic field at a point around a magnet determined? (1)
4. On what factors does the heating effect of current depend? Give one practical application
of the heating effect of electric current
5. Three resistors of 5ohm, 10ohm and 30ohm are connected in parallel to a 6V battery. Find
a) The value of current through each resistor
b) The total current in the circuit
c) And the total effective resistance of the circuit
SECTION-B
Answers
1.Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries.
2.The current is in the east-west direction. Applying the right-hand thumb rule, we get that the direction of magnetic field at a point below the wire is from north to south.
3.The direction of a magnetic field at a point is determined by placing a small compass needle. The N - pole of compass indicates the direction of magnetic field at that point.
4.The heating effect of an electric current depends on three factors: The resistance, R of the conductor. A higher resistance produces more heat. The time, t for which current flows.
5.On the attachment.
