Question bank
Practice A-Level CAIE Physics 4 3 Density And Pressure questions by syllabus topic with past-paper context, marks, difficulty and question previews on Eduninja.
Question 1
A stone sinks in water. What is a possible value for the density of the stone? \(8 \times 10^{2} \mathrm{~kg} \mathrm{~m}^{-3}\) \(2 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}\) \(8 \times 10^{3} \mathrm{Nm}^{-3}\) \(2 \times 10^{4} \mathrm{Nm}^{-3}\)
B
Question 1
A0.10 kg mass is taken to Mars and then weighed on a spring balance and on a lever balance. The acceleration due to gravity on Mars is 38\% of its value on Earth. What are the readings on the two balances on Mars? (Assume that on Earth \(g=10 \mathrm{~m} \mathrm{~s}^{-2}\).)
B
Question 1
Question 1(b)
A uniform cylinder has diameter D, length L and mass M. The density \(\rho\) of the cylinder is given by Table 1.2 shows the data obtained from an experiment to determine the density of the cylinder.
Question 1(b)(ii)
Calculate the density of the cylinder. Give your answer to three significant figures. density = \(\mathrm{kg} \mathrm{m}^{-3}\)
\(\rho=(4 \times 0.247) /\left[\pi \times\left(26.2 \times 10^{-3}\right)^{2} \times 0.162\right]\) C1 \(\rho=2.83 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}\) A1
Question 1
Question 1(a)
Question 1(a)(i)
Define pressure.
force / area (normal to the force) B1
Question 1(a)(ii)
Use the answer to (a)(i) to show that the SI base units of pressure are \(\mathrm{kg} \mathrm{m}^{-1} \mathrm{~s}^{-2}\).
( p=F / A so units are) \(\mathrm{kg} \mathrm{m} \mathrm{s}^{-2} / \mathrm{m}^{2}=\mathrm{kg} \mathrm{m}^{-1} \mathrm{~s}^{-2}\) A1
Question 1
A solid metal sphere has a diameter of \((3.42 \pm 0.02) \mathrm{cm}\) and a mass of \((67 \pm 2) \mathrm{g}\).
Question 1(a)
Calculate the density, in \(\mathrm{g} \mathrm{cm}^{-3}\), of the metal.
\(\rho=m / V\) C1 \[ \begin{aligned} V =(4 / 3) \times \pi \times r^{3} =(4 / 3) \times \pi \times(3.42 / 2)^{3} \left(=20.9 \mathrm{~cm}^{3}\right) \end{aligned} \] C1 \[ \begin{aligned} \rho =67 / 20.9 =3.2 \mathrm{~g} \mathrm{~cm}^{-3} \end{aligned} \] A1
Question 1
A cylindrical disc is shown in Fig. 1.1. The disc has diameter 28 mm and thickness 12 mm . The material of the disc has density \(6.8 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}\). Calculate, to two significant figures, the weight of the disc. weight = N
volume \(=\pi\left(14 \times 10^{-3}\right)^{2} \times 12 \times 10^{-3}\left(=7.389 \times 10^{-6} \mathrm{~m}^{3}\right)\) C1 density = mass / volume C1 weight =m g C1 \(=0.0502 \times 9.81=0.49 \mathrm{~N} \quad\) (mark not awarded if not to two s.f.) A1 [4]
Question 1
Question 1(a)
Define density.
density = mass / volume
Question 1(b)
Explain how the difference in the densities of solids, liquids and gases may be related to the spacing of their molecules.
density of liquids and solids same order as spacing similar / to about \(2 \times\) B1 density of gases much less as spacing much more or density of gases much lower hence spacing much more B1 [2]
Question 1(c)
A paving slab has a mass of 68 kg and dimensions \(50 \mathrm{~mm} \times 600 \mathrm{~mm} \times 900 \mathrm{~mm}\).
Question 1(c)(i)
Calculate the density, in \(\mathrm{kg} \mathrm{m}^{-3}\), of the material from which the paving slab is made. density = \(\mathrm{kg} \mathrm{m}^{-3}\)
density \(=68 /\left[50 \times 600 \times 900 \times 10^{-9}\right] \quad\) C1
Question 1(c)(ii)
Calculate the maximum pressure a slab could exert on the ground when resting on one of its surfaces. pressure = Pa
P=F / A C1
Question 1
Question 1(b)
A square solar panel with sides of length 1300 mm is shown in Fig. 1.1. Light is incident normally on the solar panel.
Question 1(b)(i)
The power of the light incident on the solar panel is 750 W . Calculate the intensity of the light.
I=P / A C1 \(=750 /\left(1300 \times 10^{-3}\right)^{2}\) C1 \(=440 \mathrm{~W} \mathrm{~m}^{-2}\) A1
Question 1
A sphere of radius 2.1 mm falls with terminal (constant) velocity through a liquid, as shown in Fig. 1.1. Three forces act on the moving sphere. The weight of the sphere is \(7.2 \times 10^{-4} \mathrm{~N}\) and the upthrust acting on it is \(4.8 \times 10^{-4} \mathrm{~N}\). The viscous force \(F_{\mathrm{V}}\) acting on the sphere is given by where r is the radius of the sphere, v is its velocity and k is a constant. The value of k in SI units is 17 .
Question 1(b)
Use the value of the upthrust acting on the sphere to calculate the density \(\rho\) of the liquid. \(\rho=\) \(\mathrm{kg} \mathrm{m}^{-3}\)
\[ \begin{aligned} F=\rho g V V=4 / 3 \times \pi \times\left(2.1 \times 10^{-3}\right)^{3} \quad\left(=3.88 \times 10^{-8} \mathrm{~m}^{3}\right) \end{aligned} \] C1 \(\rho=4.8 \times 10^{-4} / 9.81 \times V\) C1 \(=1300 \mathrm{~kg} \mathrm{~m}^{-3}\) A1
Question 1
The drag force \(F_{\mathrm{D}}\) acting on a sphere falling through a liquid is given by where r is the radius of the sphere, v is the speed of the sphere in the liquid and \(\eta\) is a property of the liquid called the viscosity.
Question 1(d)
Question 1(d)(i)
The density of the liquid is \(920 \mathrm{~kg} \mathrm{~m}^{-3}\). Show that the upthrust acting on the sphere is 1.0 N .
\(V=(4 / 3) \pi r^{3}\) C1 upthrust \(=(4 / 3) \times \pi \times 0.03^{3} \times 920 \times 9.81=1.0 \mathrm{~N}\) A1
Question 1(d)(ii)
Calculate the mass of the sphere. mass = kg
weight \(=1.0+0.096(=1.096 \mathrm{~N})\) C1 \[ \begin{aligned} m =1.096 / 9.81 =0.11 \mathrm{~kg} \end{aligned} \] A1