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ScotlandPhysics

Area 3: Electricity

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is an electric current, and how is it linked to electric charge?

Electrical charge carriers: current as the flow of charge, the relationship between charge, current and time, the role of electrons as charge carriers, and how current divides in series and parallel circuits.
An SQA National 5 Physics answer on electrical charge carriers, covering current as the flow of charge, the relationship Q equals I times t, electrons as the charge carriers in a metal, the difference between conductors and insulators, and how current behaves in series and parallel circuits.
9 min answer →

How much energy do electrical appliances use, and how is electrical power calculated?

Electrical power: power as energy transferred per second, the relationships linking power to current, voltage and resistance, and using power to find the energy and cost of running an appliance.
An SQA National 5 Physics answer on electrical power, covering power as energy per second, the relationships P equals I times V, P equals I squared R and P equals V squared over R, the link between power, energy and time, and how to work out the energy used and the cost of running an appliance.
10 min answer →

How are voltage, current and resistance related, and how do we combine resistors?

Ohm's law: the relationship between voltage, current and resistance, the meaning of resistance, and calculating the total resistance of resistors in series and in parallel.
An SQA National 5 Physics answer on Ohm's law, covering the relationship V equals I times R, the meaning of resistance, how a V-I graph for a resistor is a straight line through the origin, and how to calculate the total resistance of resistors combined in series and in parallel.
10 min answer →

What does voltage mean, and how is it related to the energy given to charge?

Potential difference (voltage): voltage as the energy given to each unit of charge, the relationship between energy, charge and voltage, and how voltage behaves in series and parallel circuits.
An SQA National 5 Physics answer on potential difference, covering voltage as the energy transferred to each coulomb of charge, the relationship between energy, charge and voltage, how a cell provides voltage, and how voltage is shared in series circuits and the same across parallel branches.
9 min answer →

How are real electrical and electronic circuits built, and how does a potential divider work?

Practical electrical and electronic circuits: standard circuit symbols and components, input and output devices such as the LDR and thermistor, the potential divider, and the action of switches and simple control circuits.
An SQA National 5 Physics answer on practical electrical and electronic circuits, covering standard circuit symbols, input devices such as the LDR and thermistor and output devices such as the LED and motor, how a potential divider splits a voltage, and how these are combined into simple control circuits.
10 min answer →