TEJ
Name:
Ohm’s Law & Kirchhoff's Law
Part 1: (26 marks knowledge)
1. What is the unit of resistance? Give both the word and the symbol.
The unit of resistance is Ohms (Ω)
2. What is the difference between voltage and current?
Voltage is the difference in charges between two points and current is the rate at which
charge is following.
3. What is Ohm’s Law?
V=R*I
4. What is the Formula for Power? What unit is it in?
P=V*I
The unit for this is Watt(W)
5. A power supply operates at 2 Amps and 120 Volts, what is the Power?
P=V*I
P = 120 x 2 = 240 W
The power would be 240 W
6. A power supply of 400 Watts with 50V, what is the current?
I = P/V
I = 400 / 50
I=8A
The current would be 8 amperes (A)
7. A resistance of 10 Ω is placed across a 9 V battery. What current flows through the battery?
I = V/R
I = 9 /10
I = 0.9 A
The current would be 0.9 amperes (A)
8. What is the overall resistance of a CD portable player if it is operated by a 3 V battery and 0.75
A flow through its circuitry?
R = V/I
R = 3/0.75
R = 4 ohm
The resistance would be 4 ohms (Ω)
9. What current flows between a potential difference of 120 V through a resistance of 30 Ω?
I = V/R
I = 120/30
I=4A
The current would be 4 amperes (A)
10. A motor with an operating resistance of 30 Ω is connected to a voltage source. 4.0 A of current
flow in the circuit. What is the voltage of the source?
V = I x R, V = 30 x 4, V = 120 V
The voltage would be 120 V
11. What is Kirchhoff's Current Law? State the formula
For a Series Circuit:
IT = I1 = I2 = I3…
For a Parallel Circuit:
IT = I1 + I2 + I3 ...
12. What is Kirchhoff's Resistor Law? State the formula.
For a Series Circuit:
RT = R1 + R2 + R3 ..
For a Parallel Circuit:
1 / RT = (1 / R1 ) + (1 / R2 ) + (1 / R3 )...
13. What is Kirchhoff's Voltage Law? State the
formula. For a Series Circuit:
VT = V1 + V2 + V3 ...
For a Parallel Circuit:
VT = V1 = V2 = V3…