Electricity

Question 1

EMF (Electric Motor Force)

Answer 1

The amount of chemical energy converted to electrical energy per unit charge when charge passes through a power supply

Question 2

State equation for power dissipated using current

Answer 2

P=IV or P=I^2R

Question 3

State the equation for power dissipated using potential difference

Answer 3

P=V^2/R or P=IV

Question 4

EMF

Answer 4

E/Q

Question 5

Internal Resistance

Answer 5

The opposition to the flow of current in the battery which results in voltage (potential difference) in the battery being lost and energy is transferred to heat which heats up the battery.

Question 6

Why do voltmeters have infinite resistance?

Answer 6

They have infinite resistance so that no current can flow through it whatsoever and they can only record/measure volts

Question 7

Cells arranged in parallel all have the same?

Answer 7

They have the same emf

Question 8

Voltage laws in circuits

Answer 8

In Series- Voltage is the e.m.f of the power supply is shared amongst all the components in different amounts, depending on their resistance
In Parallel- Voltage is the voltage of all the components in each branch is equal to the e.m.f of the power supply

Question 9

Current laws in circuits

Answer 9

In Series- Current is the same for all components
In Parallel- Current is split across the different branches (or junction). The total current into a junction must equal the total current out of a junction

The amount of current in each branch depends on the total resistance of the components within that branch