If a resistance is halved in value and the potential difference across it is tripled,...

PHYSICS
JAMB 1995

If a resistance is halved in value and the potential difference across it is tripled, then the ratio of the new current to the old one is

  • A. 1 : 6
  • B. 1 : 3
  • C. 2 : 1
  • D. 6 : 1

Correct Answer: D. 6 : 1

Explanation

\(\frac{V_1}{V_2}\) = \(\frac{I_1R_1}{I_2R_2}\)

\(\frac{I_1}{I_2}\)V2 = 3V1 and R1 = 2R2

\(\frac{V_1}{3V_1}\) = \(\frac{I_1 \times\ 2R_2}{I_2\times R_2}\)

\(\frac{I_1}{I_2}\) = \(\frac{6}{1}\)



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