ScienceClass 10CBSE
Q
1. A cylindrical conductor of length l and uniform area of crosssection A has resistance R. Another conductor of length 2l and resistance R of the same material has area of cross section (a) A/2 (b) 3A/2 (c) 2A (d) 3A
A
Soln:
Answer is (c) 2A
Explanation:
P=𝑅𝐴
𝑙
When Length doubles
P=𝑅𝐴
2𝑙
𝑅𝐴=𝑅𝐴
𝑙 2𝑙
A=2A