Question 41
Current ElectricityA wire P has half the diameter and half the length of a wire Q of similar material. The ratio of the resistance of P to that of Q is
- A.8 : 1
- B.4 : 1
- C.2 : 1
- D.1 : 1
- E.1 : 4
Show the answer and explanation
Answer: C (2 : 1)
Explanation
R ∝ L/d². For P: (½)/(½)² = 2 times Q's resistance, so the ratio is 2 : 1.