Electric Circuits

Question 1

When is emf equal to potential difference (voltage)?

Answer 1

When no charges are flowing in the circuit

Question 2

Important components of a circuit

Answer 2

Battery
Conducting wire
Switch
Light bulb
Resistor/rheostat 
Ammeter
Voltmeter

Question 3

What does a battery do?

Answer 3

Converts chemical energy into electrical energy

Question 4

What does conducting wires do?

Answer 4

Allows the flow of charge from one terminal of the battery to the other/through the circuit.

Question 5

Equation used for calculations with emf and potential difference

Answer 5

V = W/Q or W =VQ

W - energy transferred between two points
V - potential difference in volts
Q - Charge in coulomb

Question 6

Series circuits

Answer 6

The total potential difference is equal to the sum of the potential differences across all individual components

Rs = R1 + R2 + R3

Question 7

Parallel circuits

Answer 7

The total current in the circuit is equal to the sum of the branch currents

1/Rp = 1/R1 + 1/R2 + 1/R3

Question 8

Unit of resistance

Symbol of resistance

Answer 8

Unit - One ohm (Ω) (is equal to one volt per ampere)

Symbol - R

Question 9

Potential difference is measured in?

Answer 9

Volts (V)

Question 10

Current strength is measured in?

Answer 10

Amperes (A)

Question 11

Letter for current strength in an equation

Answer 11

Current strength = I

Question 12

Direction of conventional current

Answer 12

Direction in which positive charges move in the circuit. From the positive terminal of the battery to the negative terminal.

Question 13

Ammeter is connect in ____ and has ____ resistance

Answer 13

Connected in series

Low resistance

Question 14

Voltmeter is connect in ____ and has ____ resistance

Answer 14

Connected in parallel

Very high resistance

Question 15

Equation to calculate current strength

Answer 15

I = Q/t
I - current in amperes (A)
Q - charge in coulomb (C)
t - time in seconds (s)
Or 
I = V/R (Current strength = voltage / resistance)

Question 16

Resistance is the ____ to flow of electric charges

Answer 16

Opposition

Question 17

Factors that affect resistance

Answer 17

1. Thickness of the conductor
2. Length of the conductor
3. Temperature of the conductor
   (4. Type of material of the conductor)

Question 18

Resistance equation

Answer 18

R = V/I (known as Ohm’s law)

Question 19

Why does a battery go flat eventually?

Answer 19

All the chemical energy in the battery has been converted into electrical energy and has been transferred to the components of the circuit.

Question 20

Lower resistance characteristics of the conductor

Answer 20

Thicker, shorter, colder conductor

Question 21

High resistance characteristics of the conductor

Answer 21

Thinner, longer, warmer conductor