The correct answer is: Option (D) length, speed
Explanation:
According to Faraday's Law of Induction:
ξ = Blv
Where,
ξ = Emf Induced
B = Magnetic Induction
l = Length of the conductor
v = Speed of the conductor.
As you can see that ξ (Emf/voltage induction) is directly proportional to the length and the speed of the conductor. Therefore, the correct answer will be Option (D) Length, Speed
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