Branch, Loop and Node Analyses - Engineering

Q1:

What is the voltage drop across R1?

A 850 mV

B 7.82 V

C 9.18 V

D 918 mV

ANS:B - 7.82 V

Applying KCL at node ------>(1)
i1-i2-i3=0
then in equation 1 apply KVL
12-Va/8 - Va/37 - (Va-4)/90 = 0.
50024 - 11966Va/ 226440 = 0.
Va=4.18

Then to find the voltage drop across R1.
Remember that voltage in sires is sum up.
Vt = V1+V2+V3+......Vn.
Va = 4.18,
Va = VR1 + (-12),
VR1 = 12-4.18,
VR1 = 7.82A.