Edexcel IGCSE Physics (b) Density & pressure Question Bank

Practise density and pressure using mass, volume, area, depth and fluid data from diagrams, tables and practical contexts.

Exam points

calculate density or volume from mass data, including displaced liquid readings
apply P = F/A to explain effects of contact area,
interpret fluid pressure diagrams and use pressure difference = height x density x g

Covered syllabus points

5.3 Density equation 5.4 Density practical 5.5 Pressure equation 5.6 Pressure in fluids 5.7 Pressure difference equation

[Maximum number: 4]

This question is about liquid nitrogen.

(a)

A teacher uses this method to find the density of liquid nitrogen.
- measure the mass of a container
- pour liquid nitrogen into the container
- measure the total mass of the container and the liquid nitrogen
- read the volume of the liquid nitrogen from the scale on the side of the container

[ 4 ]

(i)

State the formula linking density, mass and volume.

[ 1 ]

(ii)

Calculate the density of the liquid nitrogen.

Give a suitable unit.

[ 3 ]

Marking points:
- substitution
- evaluation
- matching unit

Example:
$\rho=\frac{m}{V}$ $\rho=\frac{74}{88}$ $\rho=0.84\ \mathrm{g\,cm^{-3}}$

Accept:
- $0.8409090\ldots\ \mathrm{g\,cm^{-3}}$
- ECF from incorrect mass

[Maximum number: 7]

Hailstones are small pieces of ice that sometimes fall to the ground during storms.

(a)

Describe how to determine the density of a hailstone.

Assume that hailstones are spherical.

[ 4 ]

Any four from:
- measure mass
- use a mass balance
- measure diameter
- use ruler / callipers / micrometer
- further experimental detail, e.g. use set square against ruler, use callipers in different orientations, fully submerged, avoid splashing
- repeat readings and take average
- use formula to find volume of a sphere, e.g.
$V=\frac{4}{3}\pi r^{3}$
- use
$\text{density}=\frac{\text{mass}}{\text{volume}}$

Accept:
- scales for balance
- displacement method and measuring cylinder for measuring volume

Condone:
- letting the ice melt

Reject:
- scale for balance

(b)

The mean volume of a hailstone is 1.1 cm^3.

The mean mass of a hailstone is 0.94 g.
Calculate the mean density of a hailstone.
Give the unit.

density = ............ unit ............

[ 3 ]

[Maximum number: 4]

A student investigates how much pressure she exerts on the ground when she is standing up.

(a)

The student measures the area of one of her feet when it is in contact with the ground. She draws around her foot on a piece of squared paper.

Figure for Question (a) — Edexcel IGCSE Physics

[ 4 ]

(i)

State the formula linking pressure, force and area.

[ 1 ]

pressure = force / area;

Notes: allow standard symbols
and rearrangements e.g.
$\mathrm{p}=\mathrm{F} / \mathrm{A}$

(ii)

The weight of the student is 520 N.

Calculate the pressure the student exerts on the ground when she is standing on both feet.

Give the unit.

pressure = ............ unit ............

[ 3 ]

Marking points:
- dimensionally correct substitution
- evidence of doubling area or halving pressure to account for both feet
- evaluation with matching unit

Example:
$\text{pressure}=\frac{520}{156}$ $\text{area}=156\times2$ $\text{pressure}=\frac{520}{156\times2}=1.7\ \mathrm{N\,cm^{-2}}$

Accept:
- ECF from 4(b)(i)
- $\mathrm{N\,cm^{-2}}$ , $\mathrm{N\,m^{-2}}$ , or $\mathrm{Pa}$ if no marks are awarded for the calculation
- $1.5\text{--}1.8\ \mathrm{N\,cm^{-2}}$
- $15000\text{--}18000\ \mathrm{N\,m^{-2}}$

Marking guidance:
- Allow 1 mark if a valid unit for pressure is given.

All question bank results loaded

Covered syllabus points

(b) Density and pressure question 1

Question (a)

Question (i)

Question (ii)

(b) Density and pressure question 2

Question (a)

Question (b)

(b) Density and pressure question 3

Question (a)

Question (i)

Question (ii)