Question 1
1
The product of pressure and volume has the same SI base units as energy. force. force. \(\frac{\text { force }}{\text { length }}\).
Answer
A
Question bank
A-Level CAIE Physics 1 2 Si Units Question Bank
Practice A-Level CAIE Physics 1 2 Si Units questions by syllabus topic with past-paper context, marks, difficulty and question previews on Eduninja.
Question 1
1
Question 1(a)
1(a)
In the following list, underline all units that are SI base units. ampere degree Celsius kilogram newton
Answer
only ampere and kilogram underlined B1
Question 1
1
Question 1(b)
1(b)
Use the answer to (a) to determine the SI base units of power.
Answer
P=F s / t \[ =\left(\mathrm{kg} \mathrm{~m} \mathrm{~s}^{-2} \times \mathrm{m}\right) / \mathrm{s} \] C1 \(=\mathrm{kg} \mathrm{m}^{2} \mathrm{~s}^{-3}\) A1
Question 1
1
The rate of flow Q of a liquid along a narrow pipe of length L and radius r is given by where \(\alpha\) is a constant. An experiment is carried out to determine the value of \(\alpha\). The data from the experiment are shown in Table 1.1.
Question 1(a)
1(a)
Use information in Table 1.1 to show that the SI base unit of \(\alpha\) is \(\mathrm{s}^{-1}\).
Answer
(SI base unit of \(\alpha=\) ) \(\mathrm{m}^{3} \mathrm{~s}^{-1} \times \mathrm{m} / \mathrm{m}^{4}=\mathrm{s}^{-1}\) A1
Question 1
1
Question 1(a)
1(a)
Underline all the SI base units in the following list. ampere coulomb current kelvin newton
Answer
only ampere and kelvin underlined B1
Question 1
1
Question 1(b)
1(b)
A horizontal pipe has length L and a circular cross-section of radius R. A liquid of density \(\rho\) flows through the pipe. The mass m of liquid flowing through the pipe in time t is given by where \(p_{1}\) and \(p_{2}\) are the pressures at the ends of the pipe and k is a constant. Determine the SI base units of k. SI base units
Answer
unit of R: m and unit of t: s and unit of L: m C1 unit of \(\rho: \mathrm{kg} \mathrm{m}^{-3}\) or \[ \rho=m / V \] C1 base units of k : ( \(\left.\mathrm{kg} \mathrm{m}^{-1} \mathrm{~s}^{-2} \times \mathrm{m}^{4} \times \mathrm{kg} \mathrm{m}^{-3} \times \mathrm{s}\right) /(\mathrm{kg} \times \mathrm{m})=\mathrm{kg} \mathrm{m}^{-1} \mathrm{~s}^{-1}\) A1
Question 1
1
Question 1(b)
1(b)
The radius of a small sphere is determined from a measurement of the volume of the sphere. The sphere is submerged in water, displacing some of the water into a measuring cylinder as shown in Fig. 1.1. The measured volume of displaced water is \((28.0 \pm 0.5) \mathrm{cm}^{3}\). Calculate:
Question 1(b)(i)
1(b)(i)
the radius, in cm , of the sphere
Answer
\[ \begin{aligned} r =[(3 \times 28) / 4 \pi]^{1 / 3} =1.9 \mathrm{~cm} \end{aligned} \] A1
Question 1
1
Question 1(a)
1(a)
In the following list, underline all quantities that are SI base quantities. charge electric current force time
Answer
only electric current and time underlined B1
Question 1
1
Question 1(a)
1(a)
Table 1.1 lists some SI quantities. Complete the table by indicating with a tick ( \(\checkmark\) ) which rows are SI base quantities.
Answer
current and mass only ticked A1
Question 1(b)
1(b)
Use the definition of power to determine its SI base units.
Answer
(power =) work (done) / time C1 \[ \begin{aligned} \text { units of power } =\mathrm{J} \mathrm{~s}^{-1} =\mathrm{kg} \mathrm{~m}^{2} \mathrm{~s}^{-2} / \mathrm{s} =\mathrm{kg} \mathrm{~m}^{2} \mathrm{~s}^{-3} \end{aligned} \] A1
Question 1
1
The drag force \(F_{\mathrm{D}}\) acting on an object falling through air is given by where A is the cross-sectional area of the object, v is the velocity of the object in the air, \(\rho\) is the density of the air and C is a constant called the drag coefficient.
Question 1(a)
1(a)
Use SI base units to show that the drag coefficient has no units.
Answer
units of \(F_{\mathrm{D}}: \mathrm{kg} \mathrm{m} \mathrm{s}^{-2}\) M1 units of \(\rho: \mathrm{kg} \mathrm{m}^{-3}\) and units of A : \(\mathrm{m}^{2}\) and units of \(v: \mathrm{m} \mathrm{s}^{-1}\) or units of \(v^{2}: \mathrm{m}^{2} \mathrm{~s}^{-2}\) M1 \(\mathrm{kg} \mathrm{m} \mathrm{s}^{-2}=C \mathrm{~kg} \mathrm{~m} \mathrm{~s}^{-2}\) and comment '(so) C has no units' / unit terms cancelled or \(C=\mathrm{kg} \mathrm{m} \mathrm{s}^{-2} /\left(\mathrm{kg} \mathrm{m}^{-3} \mathrm{~m}^{2} \mathrm{~m}^{2} \mathrm{~s}^{-2}\right)\) and comment '(so) C has no units' / unit terms cancelled A1
Question 1(d)
1(d)
The sphere is falling in air at a terminal velocity of 25 in SI base units. The density of the air is 1.2 in SI base units. The diameter of the sphere is 0.060 in SI base units. Use your answer in (c) to calculate the drag coefficient C for the sphere.
Answer
area \(=\pi \times(0.060 / 2)^{2}\) C1 \(0.48=1 / 2 \times C \times 1.2 \times \pi \times(0.060 / 2)^{2} \times 25^{2}\) C1 C=0.45 A1