Question

Two wires are having the same lenght and same cross sectional area but one is made up of copper and one is made up of aluminium are separately connected across a potential difference of 12 V. Which one will show more flow of current? Justify.​

Answer 1

Answer:

Correct option is

C

40Ω

Resistance of a wire R=

A

ρl

where ρ= resistivity, l= length, A= cross section of the wire.

As both have same material and length so R∝

A

1

Thus,

R

1

R

2

=

A

2

A

1

=

1

3

⇒R

2

=3R

1

.

here R

1

is the resistance of thicker wire so its resistance R

1

=10Ω (given)

so, R

2

=3(10)=30Ω

As they are connected in series so the equivalent resistance is

R

eq

=R

1

+R

2

=10+30=40Ω