Topic 2 - Electricity

What is a Electric Field?

A region where a charge experiences a force.

What are two types of fields?

Radial field - The closer the field lines the stronger the field, the greater the force.

Uniform Field - Parallel lines with a constant gap.

What are the common circuit symbols?

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What is potential difference + Formula?

The amount of energy given or taken from the circuit per unit of charge flowing. V=E/Q

What is Ohm’s Law?

V=IR

What is the relationship between current and voltage?

Current is directly proportional to the voltage.

How does temperature affect resistance?

It increases the resistance of the wire(Explain with kinetic and electrons) and can cause it to overheat.

What is forward biased?

When a diode has a low resistance.

What is reverse biased?

When a diode has a high resistance.

How does the length of a wire affect the resistance?

The resistance is directly proportional to the length.

What is the relationship between light intensity and resistance when using a LDR?

The resistance is directly proportional to the light intensity,

What is the formula for power?

Power(W)=Energy(J)/Time(s)

Or

P=IV

Or

P=I²R

What is the formula for efficiency?

Efficiency=Output/Useful Input

What is the formula for frequency?

Frequency(Hz)=1/Time for 1 cycle(s)

What is the Mains Voltage?

230V

Label a Three Pin Plug

What happens if there is an earth wire and a fault?

The earth wire redirects the current so you are safe and blows the fuse so the circuit stops.

What happens if there is a fault and no earth wire?

You will experience a shock which can be fatal, as the current may pass through your body and cause serious injury or death.

How do you workout what fuse to use?

Calculate the current and choose between 3A, 5A, 10A and 13A. Choose the one above the current.

Describe a diagram of the National Grid?

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