A cylindrical wire of length L and radius r has a resistance R. The resistance of another wire of same material but of twice its length and twice its radius is:
A)4R B) R/2 C) 2R D) R
Answers
Answered by
1
The ans . is 2R.
Not sure but i think so.
Not sure but i think so.
Answered by
2
Hey dear,
● Answer -
(B) R/2
● Explaination -
# Given -
L' = 2L
r' = 2r
# Solution -
Let ρ be resistivity of material.
For first wire,
R = ρL / A
R = ρL / (πr^2)
For second wire,
R' = ρL' / (πr'^2)
R' = ρ(2L) / (4πr^2)
R' = ρL / (2πr^2)
R' = R/2
Therefore, effective resistance of second wire is R/2.
Hope this help you...
● Answer -
(B) R/2
● Explaination -
# Given -
L' = 2L
r' = 2r
# Solution -
Let ρ be resistivity of material.
For first wire,
R = ρL / A
R = ρL / (πr^2)
For second wire,
R' = ρL' / (πr'^2)
R' = ρ(2L) / (4πr^2)
R' = ρL / (2πr^2)
R' = R/2
Therefore, effective resistance of second wire is R/2.
Hope this help you...
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