Question

Consider a rectangular slab of length L and area of cross section A. A current I is passed through it. If the length is doubled, the potential drop across the end faces Options Becomes half of the initial value Becomes one-fourth of the initial value Becomes doubled the initial value ​

Answer 1

c) Becomes doubled the initial value ​

Explanation for the correct option:

• Here the potential drop across the slab will be due to the resistance.

• Whenever current passes through a material it faces some resistance which is the opposition to its flow.

• This resistance depends upon the length, area and material property of that particular substance that is responsible for the opposition e.g. resistivity.

• Hence, the formula for resistance becomes, R=ρL/A

• But we need to relate length of material that is offering resistance  and potential. So, from the formula of potential. We have, V=IR

• Putting value of R in formula of potential

• V=IρL/A

• From here, we can clearly see that potential and length are directly related to each other. That means, if you double the length, the potential drop will be doubled.

• Hence, option c) is correct.

The correct  and complete questions is

Consider a rectangular slab of length L and area of cross section A. A current I is passed through it. If the length is doubled, the potential drop across the end faces

a) Becomes half of the initial value

b) Becomes one-fourth of the initial value

c) Becomes doubled the initial value ​

d) Remains Same

#SPJ3