True False The resistance of wire B is twice as large as the resistance of wire
ID: 1532930 • Letter: T
Question
True False The resistance of wire B is twice as large as the resistance of wire A.
True False The curent through the battery is five times larger than the current through wire B.
True False The resistance of wire B is four times as large as the resistance of wire A.
True False The voltage drop across wire B is larger than the voltage drop across wire A.
True False The power dissipated in wire A is 16 times the power dissipated in wire B.
Explanation / Answer
Resistance (R) = rho * L/A = 4 rho * L/d^2
d = diameter, L = length of wire
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length = same
diameter> dA = 2 dB
so>
R(A) = R(B)/4
R(B) = 4 R(A)
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1) false > four times
2) box resistance of combination (Ro)
Ro = R(A) R(B)/[R(A) + R(B)] = 4 R(A)*R(A)/5 R(A)
Ro = [4/5] R(A)
I = current through battery = V/[4/5]R(A) = 5V/4R(A) --------- (1)
I(B) = current through B = V/R(B) = V/4 R(A) ------------ (2)
divide
I / I(B) = 5
(2) is true>>>>>
3) True > proved above
4)false> in parallel combination whatever be resistances in branches, voltage drop across each branch is SAME
5) Power = P(A) = V^2/R(A) >>>>>> at constant voltage
P(B) = V^2/R(B)
divide>
P(A)/P(B) = R(B)/R(A) = 4
its not 16 times, but 4 times
false