Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: \(\vec{J}=\sigma\vec{E}\) and \(V=IR\) both represent Ohm's law. Reason R: Resistance of a material does not depend on shape and size of material. Choose the most appropriate answer from the options given below

• A. Both A and R are correct and R is the correct explanation of A.
• B. Both A and R are correct but R is NOT the correct explanation of A.
• C. A is correct but R is not correct.
• D. A is not correct but R is correct.

Hint:

Resistance depends on length and cross-sectional area.

Answer 1

The Correct Option is C

Concept:
Ohm's law relates current density with electric field and voltage with current.
Step 1:
Microscopic Ohm's law: \[ \vec{J}=\sigma\vec{E} \] Macroscopic Ohm's law: \[ V=IR \] Thus Assertion A is correct.
Step 2:
Resistance depends on: \[ R=\rho\frac{L}{A} \] Thus it depends on length and area.
Step 3:
Reason R is incorrect.
Step 4:
\[ \boxed{\text{A is correct but R is not correct}} \] \[ \boxed{\text{Correct Option = (3)}} \]