A cell of internal resistance r is connected to an extern...
A cell of internal resistance r is connected to an external resistor R. The conductor for maximum power transfer is?
R < r
R = r
R = 2r
R > r
Correct answer is B
Power = I2R
= (ER+r)2R
To get point of maximum power transfer, we take the derivative and equate it to 0.
P=E2(R(R+r)2)
dPR=E2((R+r)2−2R(R+r)(R+r)4)
= E2((R+r)[(R+r)−2R(R+r)4)
dPdR=E2(r−R(R+r)3)
Maximum power is gotten when r - R = 0 i.e. r = R.
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