Physics
A coil wound around a piece of soft iron can become an electromagnet only when:
- the circuit is open.
- a magnetic compass is present in the vicinity.
- a galvanometer is connected to the circuit.
- a current flows in the circuit.
Electro-Magnetism
ICSE 2022
14 Likes
Answer
a current flows in the circuit.
Reason — When the current flows through the soft iron piece in the form of a closed ring, it becomes magnetised.
Answered By
7 Likes
Related Questions
A main switch in the main distribution board is present in :
- a live wire
- a neutral wire
- a live as well as neutral wire
- an earth wire
A conductor AB is kept along north south direction of the earth above a magnetic needle as shown below. When the key K is closed then:
- the needle will not show any deflection.
- the needle will deflect towards east.
- the needle will turn in the opposite direction i.e. towards south.
- the needle will deflect towards west.
If water absorbs 4000 joule heat to increase the temperature of 1 kg water through 1°C then the specific heat capacity of water is :
- 4 Jkg-1°C-1
- 400 Jg-1°C-1
- 4 Jg-1°C-1
- 4.2 Jg-1°C-1
Water is used in car radiators because :
- it is a good conductor of heat.
- it conducts heat faster as compared to the other substances and cools the engine quickly.
- its specific heat capacity is very low.
- its specific heat capacity is very high so it can cool the engine without a greater increase in its own temperature.