Series-Parallel Circuits - Technical MCQs

Q1:

The voltmeter will read 18 volts.

tfq5_1011_1.gif

A True

B False

ANS:A - True

Lets say point between R8 and R10 be A and point between R7 and R9 be B.

Now, R8, R10 in series so Rt1 = 2+3 = 5 ohm.

And R7, R9 in series so Rt2 = 1+4 = 5 ohm.

Rt=(Rt1Rt2)/(Rt1+Rt2) = 5/2 ohm.

Total current = V/Rt = (90*2)/5 = 36 amp.

Since Rt1 and Rt2 are equal therefore equal current will flow through each branch = 36/2 = 18 amp.

Voltage drop across R8 = 18*2 = 36v.

Potential at point A = 90-36 = 54v.

Voltage drop across R7 = 18*1 = 18v.

Potential at point B = 90-18 = 72v.

Potential diff. between A and B gives voltmeter reading = 72-54 = 18v.