AQA Physics Paper 1 Flashcards (76 cards)

Where are an atom’s protons and neutrons located?

In its nucleus.

Where are an atom’s electrons located?

Around the nucleus.

What defines isotopes of the same element?

They have the same number of protons but different numbers of neutrons.

What does the activity of a radioactive source measure?

The rate at which its unstable nuclei decay.

In what unit is radioactive activity measured?

Becquerels (Bq).

Which instrument measures a radioactive source’s activity?

A Geiger–Müller tube.

How do alpha, beta, and gamma radiation differ?

In penetration through materials, range in air, and ionising power.

What does the half-life of a radioactive isotope describe?

The time taken for its undecayed nuclei or activity to halve.

What distinguishes radioactive contamination from irradiation?

Contamination involves radioactive material on or inside an object; irradiation does not transfer radioactive material.

What formula calculates density from mass and volume?

$\rho = \frac{m}{V}$

How are particles arranged and how do they move in solids?

They are closely packed in fixed arrangements.

How do particles move in liquids?

They remain close together and move past one another.

How are particles spaced and how do they move in gases?

They are widely spaced and move freely.

What happens to a substance’s mass during a change of state?

Its mass remains unchanged.

How does a change of state affect a substance’s properties?

It changes the substance’s properties reversibly.

What does internal energy include for all particles in a system?

Their total kinetic and potential energy.

What formula calculates the change in thermal energy?

$\Delta E = mc\Delta\theta$

What formula calculates energy transferred during a change of state?

$E = mL$

What does specific heat capacity describe?

The energy needed to change temperature.

What does specific latent heat describe?

Energy transferred during a change of state.

How do gas molecules move?

They move constantly and randomly.

How does higher gas temperature affect average molecular kinetic energy?

It increases average kinetic energy.

What happens to gas pressure when a gas is heated at constant volume?

Its pressure rises.

Why does heating a gas at constant volume raise its pressure?

Particles collide with the container walls more forcefully.

How does increasing pressure affect the volume of a fixed gas mass at constant temperature?

It decreases the volume.

How does decreasing pressure affect the volume of a fixed gas mass at constant temperature?

It increases the volume.

What formula calculates electrical power using voltage and current?

$P = VI$

What formula calculates electrical power using current and resistance?

$P = I^2R$

What formula calculates electrical energy transferred using power and time?

$E = Pt$

What formula calculates electrical energy transferred using charge and potential difference?

$E = QV$

How does raising potential difference improve energy transfer in the National Grid?

It reduces current, making energy transfer more efficient.

What is electric current?

The rate of flow of electrical charge around a closed circuit.

What equation relates charge, current, and time?

$Q = It$

What causes current in a closed loop, and how does its value vary around the loop?

A source’s potential difference causes current, which has the same value at every point in the loop.

What equation relates potential difference, current, and resistance?

$V = IR$

What is the current relationship among components connected in series?

The same current passes through every component.

What is the potential-difference relationship among components connected in parallel?

Each component has the same potential difference.

What is the total-resistance formula for two series components?

$R_{\text{total}} = R_1 + R_2$

How does adding resistors in series affect total resistance?

It increases total resistance.

How does adding resistors in parallel affect total resistance?

It decreases total resistance.

How do alternating current and voltage differ from direct current and voltage?

Alternating current and voltage periodically change direction; direct current and voltage remain in one direction.

What type of current does UK mains electricity use?

Alternating current.

What is the potential difference between the live wire and earth?

About 230 V.

What is the potential of neutral wires and human bodies relative to earth?

At or close to 0 V.

Why can a live wire remain dangerous when the mains switch is open?

A connection between the live wire and earth can cause harm.

What is a system in energy-store analysis?

An object or group of objects whose energy stores can change.

What formula calculates an object's kinetic energy?

$E_k = \frac{1}{2}mv^2$

What formula calculates gravitational potential energy gained above ground?

$E_p = mgh$

What does power measure?

The rate at which energy is transferred or work is done.

How much energy does one watt transfer per second?

One joule.

What happens to total energy in a system when energy is transferred, stored, or dissipated?

It does not change.

What happens to energy that is not transferred usefully in a system?

It is wasted.

What can be done to unwanted energy transfers in a system?

They can be reduced.

How is efficiency calculated from useful power output and total power input?

$\text{efficiency} = \frac{\text{useful power output}}{\text{total power input}}$

What makes an energy resource renewable?

It is replenished naturally.

Which considerations and limitations are involved in evaluating energy resources?

Environmental, ethical, political, social, and economic considerations and limitations.

What does the conventional representation of a nucleus identify?

Its element.

Which numbers does the conventional representation of a nucleus give?

Its proton number and mass number.

What led scientists to change the atomic model over time?

Experimental evidence, including scattering experiments and James Chadwick’s work.

Which quantities must a balanced nuclear equation conserve?

Total atomic number and total mass number.

How does peer review help check studies of radiation effects on humans?

Scientists can check published findings shared with them.

What does the required practical determine for solids and liquids?

Their densities, using measurements of mass and volume.

Which processes are changes of state?

Melting, freezing, evaporating, condensing, subliming, and deposition.

What can heating and cooling graphs show?

Temperature changes and plateaus during changes of state.

What energy form do motors transfer electrical energy into?

Kinetic energy.

What energy form do heating devices transfer electrical energy into?

Thermal energy.

What does a domestic appliance’s power rating describe?

The rate at which it transfers energy and changes energy stores while in use.

At a given potential difference, what happens to current when resistance increases?

The current decreases.

How can series-resistor circuit problems be simplified?

Replace the resistors with their equivalent total resistance.

Which three wires are contained in a three-core mains cable?

Live, neutral, and earth wires.

What formula calculates elastic potential energy in a stretched spring?

$E_e = \frac{1}{2}ke^2$

What is specific heat capacity?

The energy required to raise a unit mass of a substance by one degree.

Which factors determine how quickly a building cools?

Wall thickness and thermal conductivity.

What can be proposed to improve an intended energy transfer?

Ways to increase its efficiency.

Which uses can be compared when assessing energy resources?

Transport, electricity generation, and heating.

What can differ between energy resources, and what can be explained about their use?

Their reliability differs, and patterns and trends in their use can be explained.