Advertisements
Advertisements
Question
What device reverses the current?
Solution
A commutator (split rings) reverses the current.
APPEARS IN
RELATED QUESTIONS
When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
For the coil in the diagram below, when the switch is pressed:
(a) what is the polarity of end A?
(b) which way will the compass point then?
In the Activity shown below, how do we think the displacement of rod AB will be affected if
- current in rod AB is increased
- a stronger horse-shoe magnet is used
- length of the rod AB is increased?
|
(b) State whether the following statements are true or false:
(i) Magnetic poles exist in pairs.
(ii) Global warming is a desirable aspect of the intensified greenhouse effect.
Read the given passage and answer the following questions:
The home electrical connection consists of ‘live’, ‘neutral’ and ‘earth’ wires. The ‘live’ and the ‘neutral’ wires have potential difference of 220 V. The ‘earth’ is connected to ground. Due to a fault in the equipment or if the plastic coating on the ‘live’ and the ‘neutral’ wires gives a way the two wires come in contact with each other and a large current flows through it producing heat. If any inflammable material (such as wood, cloth, plastic, etc.) exists around that place it can catch fire. Therefore a fuse wire is used as a precautionary measure.
- Name the two wires having potential difference of 220 V.
- What is a short circuit?
- Write the function of a fuse.
Identify the given figure, write the labels of it.
Explain the magnetic field created around a straight current carrying conductor with the help of a diagram.
What is that instrument which can detect the presence of electric current in a circuit?
Magnetic effect of current was discovered by ______.
An electric bell contains an ______, consisting of coils of insulated wire wound around
iron rods.
