A conductor has resistance R. If its length is stretched to twice the actual and its radius is reduced to one third of its original value, the new resistance will be:
Correct answer: C. 18R
- A. 3R
- B. 9R
- C. 18R
- D. 27R
Explanation
Resistance is given by:⇒ R = ρ L / ASince, A = π r^2If its length is doubled its original value and its radius is reduced to one-third of its original value, then the area is reduced to one-ninth of its original value.⇒ R = ρ 2L / A/9⇒ R = 18 x ρ L / A⇒ R = 18RDiagram:
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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.
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