NTA Abhyas JEE Main2020PhysicsCurrent ElectricityPractice
The V - I graphs for a conductor at temperature T 1 and T 2 are shown in the figure. T 2 - T 1 is proportional to
Options
- Atan θ
- Bsin θ
- Ccot 2 θ
- Dcos 2 θ
Correct answer
C. cot 2 θ
Step-by-step solution
The slope of V - I graph gives resistance, R 1 = tanθ ,   R 2 = tan ( 90 - θ ) = cotθ R 1 = R 0 ( 1 + αT 1 ) and R 2 = R 0 ( 1 + αT 2 ) ∴ R 2 - R 1 = R 0 α ( T 2 - T 1 ) ⇒ cotθ - tanθ = R 0 α ( T 2 - T 1 ) ∴ T 2 - T 1 ∝ cosθ sinθ - sinθ cosθ ∝ 2 ( cos 2 θ - sin 2 θ ) 2 sinθ ⋅ cosθ ∝ 2 c o s 2 θ s i n 2 θ ∴ T 2 - T 1 ∝ cot 2 θ