An ammeter of full scale deflection 5.00 mA is being used to read a current of size 5.00 A.
This can be achieved by:
Connecting it in parallel with a resistance of 49.95 Ω.
Connecting it series with a resistance of 980.00 Ω.
Connecting it in parallel with a resistance of 0.02 Ω.
Connecting it in parallel with a resistance of 0.49 Ω.
The heating element of an electric kettle has a resistance of 30.0 Ω.
The kettle is connected to an a.c. power supply of root means square voltage 230 V.
The peak value of the current is:
15.2 A.
10.8 A.
5.4 A.
7.7 A.
The set up in the figure is used to study the relationship between current (I) and potential difference (V) for a wire X.
The rheostat Y is used to:
Keep the temperature constant.
Vary the current in the circuit.
Vary the resistance of the wire.
Vary electromotive force.
If the material X is a copper wire, the relationship between V and I when the switch is closed at constant temperature is:
Ohm’s law.
Hooke’s law.
Lenz’s law.
Coulomb’s law.
Which of the following statements describes an electric generator?
Forces from a permanent magnet allow a coil of wire to rotate.
A coil of wire is rotated through a strong magnetic field to produce an electric current.
An electrical current causes a coil of wire to rotate in a magnetic field.
Electric potential in a rotating coil of a wire creates a temporary magnet.
