5.2 Electric Circuits

Question 1

Electric Current

Answer 1

When current is flowing
- Moving Charges
-

Question 2

Potential Difference

Answer 2

Whenever there is a potential difference there is an electric field

Question 3

Ohm’s Law

Answer 3

The current flowing through a piece of metal is proportional to the potential difference across when the temperature remains constant.

V ∝ I

Question 4

Electrical Resistance (R)

Answer 4

Property of a conductor that determines how much current will flow for a given potential difference.

R = V/I in volts per ampere (ohm Ω)

Conducting wires resistance is ignored

Question 5

Ohmic vs Non-ohmic

Answer 5

Ohmic has directly proportional relationship between V and I whereas non-ohmic does not.

Question 6

What affects Resistance?

Answer 6

Of a wire kept at constant temperature

• Nature of material
• Length of wire (longer = resistance)
• The cross sectional area of the wire (more area = less resistance)
• For most metals a > temp = > resistance

Question 7

Resistivity

Answer 7

Electrical Resistance of a wire (fxed temp) is proportional to its length

Question 8

Series Circuits

Answer 8

Components connected one after another in a continuous chain. Current is same in all parts of the circuit since the charge must be conserved.

V1 = V2 + V3 + V4
I1 = I2 = I3 = I4

Question 9

Resistors in Series

Answer 9

RT = R1 + R2 + R3
VT = I x RT
Total Voltage = Current x Total Resistance

Question 10

Parallel Circuits

Answer 10

Branches out and allows the charges more than one possible route around the circuit.

I1 = I2 + I3 + I4
V1 = V2 = V3 = V4

Question 11

Resistors in Parallel

Answer 11

1/RT = 1/R1 + 1/R2 + 1/R3