When the length and area of cross-section both are doubled, then its resistance:
Correct answer: B. Will remain the same
- A. Will become half
- B. Will remain the same
- C. Will be doubled
- D. Will become four times
Explanation
Resistance is given by R = ρL/A. If the new length is L' = 2L and the new area is A' = 2A, the new resistance is R' = ρ(2L)/(2A) = ρL/A = R. The resistance remains unchanged.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Current Electricity
Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
Practise Current Electricity
1,052 free Current Electricity MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Current Electricity questions
The resistance of a wire of uniform diameter D and length L is R. The resistance of another wire of the same material but diameter 2D and length 4L will be:
The following four wires are made of the same material and are at the same temperature. Which one of them has highest electrical resistance?
Which equation is used to define resistance?
The example for non-ohmic resistance is:
A wire 100cm long and 2.0 mm in diameter has a resistance of 0.7 ohm. The electrical resistivity of the material is:
A wire of resistance R is stretched uniformly four times its length. Its new resistance will be: