Electromotive_Force_and_Potential_difference

Gap-fill exercise

Fill in all the gaps.
   Cell      circuit      converted      Coulomb      Current      energy      field      parallel      points      Power      rate      same      second      Series      Volt      Voltage      Voltmeter      work   
Electromotive Force and Potential difference

Electrical Power, Potential difference and Current



Power is defined as the at which is done

or

Power is the rate at which is from one form to another.

Most energy conversions in this section involve electrical energy converting to heat energy.

= Work / Time

P = W / t

Remember 1 watt = 1 joule per

We can change W = V X Q to P = I X V by ..........

Now if we take W = V X Q and divide both sides by time (t), we get P = VI (because W / t = P, and Q/t = I)

P = I X V

P =

I =

V =

Measuring Potential Difference

• Voltages in : V total = V 1+ V 2
• Voltages in parallel are the .
• A is used to measure Potential Difference.
• A Voltmeter is always connected in with whatever it is measuring.

The Potential difference (p.d.) between two in an electric is the done in bringing a charge of 1 from one point to the other.

Electromotive Force (emf)

A Voltage when applied to a full is called an emf.

The unit of emf is also the

Some Sources of Electromotive Force (emf)
• Mains
• Simple
• Lead-acid accumulator
• Dry batteries
• Thermocouple