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1. Define the unit of current.
 
The SI unit of the electric current is  (\(A\)).

One ampere is defined as the amount of current flowing through any cross-section of a conductor when  of charge flows through it in .
 
Mathematically,
 
2. What happens to the resistance, as the conductor is made thicker?
 
In any electrical experiment, it is proved that the conductor's resistance is proportional to its  and inversely proportional to its .
 
Hence, the resistance as the conductor is made thicker.
 
3. Why is tungsten metal used in bulbs, but not in fuse wires?
 
An electric fuse is a safety device that  to electrical appliances due to excessive current flow.
 
The fuse wire should  easily when it reaches a .
 
So, the material should have a , but tungsten is not. Hence, tungsten is commonly used as a filament in electric bulbs.
 
4. Name any two devices, which are working on the heating effect of the electric current.
 
Some of the electrical appliances contains heating element in it. They are  and .