Basic Electrical Engineering Questions and Answers Part-3

1. Find the value of v if v1=20V and value of current source is 6A.
q21
a) 10V
b) 12V
c) 14V
d) 16V

Answer: b
Explanation: The current through the 10 ohm resistor=v1/10=2A.Applying KCL at node 1: i5=i10+i2. i2=6-2=4A.
Thus the drop in the 2 ohm resistor = 4×2 = 8V.
v1=20V; hence v2=20-v across 2 ohm resistor=20-8=12V
v2=v since they are connected in parallel.
v=12V.

2. Calculate the current A.
q22
a) 5A
b) 10A
c) 15A
d) 20A

Answer: c
Explanation: KCl states that the total current leaving the junction is equal to the current entering it. In this case, the current entering the junction is 5A+10A=15A.

3. Calculate the current across the 20 ohm resistor.
q23
a) 20A
b) 1A
c) 0.67A
d) 0.33A

Answer: d
Explanation: Assume lower terminal of 20 ohm at 0V and upper terminal at V volt and applying KCL, we get V/10 +V/20 =1. V=20/3V So current through 20 ohm = V/20 = (20/3)/20 =1/3=0.33V.

4. Calculate the value of I3, if I1= 2A and I2=3A.
q24
a) -5A
b) 5A
c) 1A
d) -1A

Answer: a
Explanation: According to KCl, I1+I2+I3=0. Hence I3=-(I1+I2)=-5A.

5. Find the value of i2, i4 and i5 if i1=3A, i3=1A and i6=1A.
q25
a) 2,-1,2
b) 4,-2,4
c) 2,1,2
d) 4,2,4

Answer: a
Explanation: At junction a: i1-i3-i2=0. i2=2A.
At junction b: i4+i2-i6=0. i4=-1A.
At junction c: i3-i5-i4=0. i5=2A.

6. What is the value of current if a 50C charge flows in a conductor over a period of 5 seconds?
a) 5A
b) 10A
c) 15A
d) 20A

Answer: b
Explanation: Current=Charge/Time. Here charge = 50c and time = 5seconds, so current = 50/5 = 10A.

7. KCL deals with the conservation of?
a) Momentum
b) Mass
c) Potential Energy
d) Charge

Answer: d
Explanation: KCL states that the amount of charge entering a junction is equal to the amount of charge leaving it, hence it is the conservation of charge.

8. KCL is applied at _________
a) Loop
b) Node
c) Both loop and node
d) Neither loop nor node

Answer: b
Explanation: KCL states that the amount of charge leaving a node is equal to the amount of charge entering it, hence it is applied at nodes.

9. KCL can be applied for __________
a) Planar networks
b) Non-planar networks
c) Both planar and non-planar
d) Neither planar nor non-planar

Answer: c
Explanation: KCL is applied for different nodes of a network whether it is planar or non-planar.

10. What is the value of the current I?
q30
a) 8A
b) 7A
c) 6A
d) 5A

Answer: a
Explanation: At the junction, I-2+3-4-5=0. Hence I=8A.