PHYSICs Paper 1:

Renewable energy sources

Energy sources that are replenished naturally; examples include solar and wind.

Efficiency formula

Efficiency = (useful output / total input) × 100.

Unit of energy

Joules (J).

Kinetic energy store

Energy associated with the movement of objects.

Kinetic energy formula

KE = 0.5 × mass × velocity².

Gravitational potential energy formula

GPE = mass × gravity × height.

Specific heat capacity

Energy needed to raise the temperature of 1 kg by 1°C.

Unit of power

Watts (W).

Work done formula

Work = force × distance.

Conduction

Energy transfer method involving vibrations through solids.

Convection

Energy transfer method involving movement of fluids.

Lubricant

A device that reduces energy wasted by friction.

Elastic potential energy

Energy stored in compressed or stretched objects, such as springs.

Conservation of energy

Idea that energy cannot be created or destroyed.

Power formula from work done

Power = work done / time.

LED lightbulb

The most efficient type of lightbulb.

Double glazing effect

Reduces heat loss by creating air gap that slows conduction.

Sankey diagram

An energy dissipation diagram showing energy flow.

Electric fan

An appliance that converts electrical energy into kinetic energy.

Energy transfer in a hairdryer

Electrical → thermal + kinetic + sound.

Kilowatt-hour (kWh)

The national unit of electricity.

Solar panel function

Generates electricity by absorbing sunlight using photovoltaic cells.

Chemical energy in a battery

Energy stored in batteries.

Wasted energy from light bulbs

Heat energy lost during operation.

Coal

The fuel type that emits the most CO₂.

Energy transferred using charge formula

Energy = charge × voltage.

Hydroelectric power

Renewable because the water cycle is continuous.

Loft insulation

Process that reduces heat transfer via conduction and convection.

Chemical energy in food

Energy stored in food.

Non-renewable fossil fuels

Fossil fuels take millions of years to form.

Power rating of a kettle

Typically around 2 kW.

Power rating significance

Indicates how much energy an appliance uses per second.

High specific heat capacity

Means it takes more energy to heat up the material.

Cavity wall insulation functionality

Traps air to reduce heat transfer.

Radiation transfer prevention by shiny surfaces

High reflectivity reduces radiation transfer.

UK national average voltage

230 V.

Thermal conductivity definition

Measure of how well a material conducts heat.

Copper

A metal with high thermal conductivity.

Polystyrene insulator property

It traps air, making it a good insulator.

Cost formula using kWh

Cost = power × time × price per unit.

Specific heat capacity unit

J/kg°C.

Causes of energy wastage

Friction, resistance, and unwanted heat.

Wasted energy disposition

Energy that dissipates into the surroundings.

Best radiation emitting surface

Dull, black surfaces emit radiation best.

Most efficient energy resource

Hydroelectric energy has very little energy loss.

Power measurement

The rate of energy transfer.

Insulation definition

Material that reduces energy transfer.

Kinetic energy in a moving car

Energy associated with the motion of the car.

Energy change in a falling object

Gravitational potential energy converts to kinetic energy.

Current unit

Ampere (A).

Voltage, current and resistance relationship formula

V = I × R.

Resistance unit

Ohms (Ω).

Voltage unit

Volts (V).

Fuse function

Melts and breaks the circuit if the current exceeds safe levels.

UK mains voltage

230 V.

Mains electricity type

Alternating current (AC).

Battery current type

Direct current (DC).

Frequency of UK mains electricity

50 Hz.

Earth wire role

Safety feature that grounds current to prevent shock.

Live wire color in UK plug

Brown.

Neutral wire color in UK plug

Blue.

Earth wire color in UK plug

Green and yellow.

Power formula using voltage and current

Power = voltage × current.

Energy transfer formula

Energy = power × time.

Linking formula for energy, charge, and voltage

E = Q × V.

Ohmic conductor behavior

Obeys Ohm’s law; current and voltage are directly proportional.

Filament lamp graph behavior

Produces a curve graph; resistance increases with temperature.

Diode function

Allows current to flow in only one direction.

Total resistance in series calculation

Add all resistors: R_total = R₁ + R₂ + …

Current sharing in parallel circuits

Current is shared between branches.

Voltage in parallel circuits

Remains constant across all branches.

National Grid definition

A system of cables and transformers that distribute electricity.

Voltage increase before long-distance transmission reason

To reduce current and energy loss as heat.

Step-up transformer function

Increases voltage, decreases current.

Step-down transformer function

Decreases voltage to safe levels.

Typical fuse rating for a kettle

13 A.

Resistor function

Limits the flow of current in a circuit.

Static electricity cause

Caused by friction transferring electrons.

Electric field definition

A region around a charged object where forces are felt.

Touching a live wire consequence

Could result in an electric shock.

Resistance change with wire length

Resistance increases as wire length increases.

Material with low resistance

Copper.

Double insulation purpose

No exposed metal to protect the user.

Current increase effect with voltage increase (constant resistance)

Current increases.

Circuit type used in household lighting

Parallel circuit.

Total resistance change in parallel circuit with added branches

Total resistance decreases.

Variable resistor definition

A resistor whose resistance can be adjusted.

Thermistor function

Resistance decreases as temperature increases.

LDR function

Resistance decreases as light intensity increases.

Fuse symbol in circuit diagrams

A rectangle with a line through it.

Energy transfer in a heater

Electrical to thermal.

Power calculation for current = 5 A and voltage = 230 V

P = IV = 1150 W.

Resistance formula using voltage and current

R = V / I.

Charge unit

Coulombs (C).

Circuit breaker function

Breaks the circuit when the current exceeds safe levels.

Resistance effect on current

Higher resistance results in lower current.

Alternating current definition

Current that changes direction.

Direct current definition

Current that flows in a single direction.

Plug safety features

Fuse, earth wire, and insulation.

Density formula

Density = mass / volume.