Two wire A & B are of the same metal and are of same length have area of cross section in the ratio of `2:1` If the same potential difference is applied across each wire. What will be the ratio of the current flowing through the wires A & B ?

Explanation

The area of cross-section of two wires `=2:1`
Resistance of cross-section of two wires `=1:2`
`R alpha (rho l)/(A) i.e., R alpha=(1)/(R)`
Accroding to ohm's law
`I prop (V)/(R) i.e., I alpha (I)/(R)`
The current in the two wires `2:1` when the same potential difference is applied across the two wires. When the temperature of a conductor is increases, the amplitude of vibrate of the positive ions in hte conductor inccreases. Consequently the free electrons collide more frequently with the vibrating ions. This decreases relaxation time `tau. rho alpha (1)/(tau)`. So resistantly increases.