Question

what is meant by resistance of a conductor state how resistance of a conductor is effected when
a. a low current passes through ot for a short duration
b .. a heavy current passes through about 30 seconds ​

Answer 1

Answer:

Resistance is defined as the opposition to the flow of electrical current through a conductor. It's important to point out that conductivity and resistivity (the property that determines final resistance) are inversely proportional.

Explanation:

Let new length = l' new Area =, A' and new resistance = R' Given, l' = 2l and A' = A/2 As we know R = (ρl) / A So, R' = [ρ × 2l] / (A/2) = (4 × ρl) / A = 4 × (ρ l / A ) but R = ρl/A ⇒ R' = 4 ×R Resitivity depends on the nature of material not on the length, temperature or Area of cross-section. So, resitivity will remain Constant.

Answer 2

hi

The obstruction offered, by the positive ions present in a conductor, to the flow of current through a conductor is known as RESISTANCE.

a) When a low current is passed for a long time, due to the heat effect of current, the temperature of the conductor will increase. Resistance is directly proportional to temperature.

Thus, resistance will increase.

b) When a high current is passed for 30 seconds,

same heat effect of current will make the temperature high and resistance also high.

Note- Resistance in the case 'b' will be more than the resistance in case 'a'.

Heat formed= I^2Rt

hope it helps you