Question

The V-I graph for two ohmic conductors are as shown in the figure. The ratio of
resistances of conductor 1 and conductor 2 is:

Answer 1

Explanation:

For conductors resistance is directly proportional to the temperature. From given graph we can write

R

2

∝T

2

slope of the graph is tanθ=

i

V

=R

⇒tanθ∝T

2

⇒tanθ=KT

2

..........(K is constant ).......................................................(1)

Similarly,

R

1

∝T

1

⇒tan(90

∘

−θ)∝T

1

⇒cotθ=KT

1

..........(K is constant ).................................................................(2)

From (1) and (2)

T

2

T

1

=

tanθ

cotθ

T

2

T

1

=cotθ(

tanθ

1

)

T

2

T

1

=cot

2

θ...........( since, cotθ=

tanθ

1

)