OCR A-Level Physics A Particles and medical physics overview quiz quiz

The reciprocals add

The product over the sum

The total is the smaller capacitance

The capacitances add directly

37 per cent

50 per cent

63 per cent

10 per cent

$CV^2$

$\frac{1}{2}CV^2$

$\frac{1}{2}C^2V$

$\frac{1}{2}QV^2$

Both forces are always attractive, so neither the electric nor the gravitational force can repel

Gravitational potential varies as $\frac{1}{r^2}$, in the same way as the field strength does

Both obey an inverse-square law, but only the electric force can be repulsive

The electric force is always weaker than the gravitational force at any separation between bodies

A straight line

A parabola

A spiral that speeds up

A circle

A steady current gives a constant flux, so no emf is induced in the secondary

The wires of the primary coil would simply overheat and melt before any emf could appear

A direct current cannot flow through a coil of wire at all, so the primary carries no current

The iron core would become permanently magnetised and so block any transfer of energy across

Density increases steadily with nucleon number, so heavy nuclei are far denser than light ones

Density is approximately the same for all nuclei

Density decreases steadily with nucleon number, so light nuclei are far denser than heavy ones

Density depends on the charge of the nucleus, so it rises with the number of protons present

An up quark becomes a down quark

A proton becomes an alpha particle

A down quark becomes an up quark

Two quarks annihilate

Both completely destroy the mass of the reacting nuclei, converting all of it into energy

Both occur only at room temperature, with no extreme conditions of heat or pressure needed

Both reduce the total number of nucleons present, so nucleons are lost during the reaction

Both produce nuclei with a higher binding energy per nucleon

$\frac{1}{8}$

$\frac{1}{2}$

$\frac{1}{4}$

$\frac{1}{16}$

$0.12\ \text{m}$

$0.060\ \text{m}$

$0.030\ \text{m}$

$0.24\ \text{m}$