Physical quantities and units — AS & A Level Physics (9702) questions by topic

Which quantity is a vector? A pressure B temperature C weight D work

Four students, A, B, C and D, have completed an experiment to determine the acceleration of free fall, g. Each student repeated the experiment three times. The determined values…

The diameter of a ball is measured as (5.26 ± 0.02) cm. What is the absolute uncertainty in the volume of the ball? A 0.29 cm³ B 0.87 cm³ C 1.1 cm³ D 7.0 cm³

Two vectors, X and Y, are shown. X points up and to the right; Y points down and to the right. What are the directions of X + Y and X – Y? X + Y X – Y --- --- --- A rightward…

What must all physical quantities have? A a direction and a magnitude B a direction and a unit C a magnitude and a prefix D a magnitude and a unit

What is 0.25 kN mm^-2 expressed in N m^-2? A 0.00025 N m^-2 B 0.25 N m^-2 C 250 000 N m^-2 D 250 000 000 N m^-2

A student calculates the density of a solid steel cube in an experiment. The measured mass is 975 g ± 10 g and the measured length of side is 50 mm ± 1 mm. What is the density of…

The time period T of a pendulum is given by T = 2π(L/g)^n, where L is the length of the pendulum and g is the acceleration of free fall. The equation is homogeneous. What is the…

What represents a vector quantity? A 1 N upwards B 2 kg decrease C 3 K cooler D 4 s later

What is a reasonable estimate of the current in an electric kettle when it is heating water? A 8 μA B 8 mA C 8 A D 8 kA

Which statement about errors in measurements is correct? A A measurement with a small random error is described as having high accuracy. B A measurement with a small random error…

The rate of thermal conduction Q/t through a material is given by: Q/t = kA(T₁ – T₂) / L where A is the cross-sectional area, T₁ and T₂ are temperatures, L is the thickness, and k…

The number of atoms in a mobile phone handset may be estimated by dividing the approximate volume of the handset by the approximate volume of an atom. What is a reasonable…

Which unit is NOT equivalent to a unit of energy? A N m B V C C W s D kg m s⁻²

Calipers are used to determine the thickness of the wall of a glass tube. The following measurements are made: internal diameter of the tube = (10.0 ± 0.1) mm external diameter of…

A table lists the following five quantities: acceleration, displacement, gravitational potential energy, speed, temperature. Identify each quantity as either a vector or a scalar.

Which unit is an SI base unit? A ampere B coulomb C degree Celsius D gram

Which of the following could have the same units as force? A energy / distance B energy / time C momentum × distance D momentum × time

Which calculation produces a vector quantity? A current × time B final displacement − initial displacement C work done / time D ½ × mass × (speed)²

A thermometer can be read to an accuracy of ±0.5°C. This thermometer is used to measure a temperature rise from 40°C to 100°C. What is the percentage uncertainty in the…

What is a scalar quantity? A a quantity that can be represented as two perpendicular components B a quantity that does not require a unit C a quantity without a direction D a…

The value of quantity X has a percentage uncertainty of 2%. The value of quantity Y has a percentage uncertainty of 4%. The value of a quantity W is calculated from the values of…

What is equal to 0.000005 J? A 5 mJ B 5 MJ C 5 μJ D 5 nJ

The measurement of a physical quantity may be subject to random errors and to systematic errors. Which statement is correct? A A systematic error cannot be reduced by adjusting…

The Young modulus of the material of a wire is to be found. The Young modulus E is given by the equation E = 4FL / (πd²x). The wire is extended by a known force and the following…

Two physical quantities combined together as a product can produce a scalar quantity or a vector quantity. Which product of two quantities produces a scalar quantity? A (force) ×…

The drag force FD acting on an object falling through air is given by FD = (1/2) C rho A v^2, where A is the cross-sectional area of the object, v is the velocity of the object in…

The drag force FD acting on a sphere falling through a liquid is given by FD = 6 pi eta r v, where r is the radius of the sphere, v is the speed of the sphere in the liquid and…

What are the SI base units for the moment of a force? A kg m^-1 s^2 B kg s^-2 C kg m s^-2 D kg m^2 s^-2

Which statement about vector quantities is correct? A Acceleration of free fall is a vector quantity because it has a constant magnitude. B Temperature in degrees C is a vector…

What is a reasonable estimate of the volume of one page from this examination paper? A 60 mm^3 B 600 mm^3 C 6000 mm^3 D 60 000 mm^3

A physical quantity consists of a magnitude and a unit. Which row does not show a correct combination of a quantity and its unit? quantity unit --- --- --- A mass gram B length…

Which statement about physical quantities is correct? A A physical quantity does not always have a magnitude or a unit. B A physical quantity must always have a magnitude but does…

What is a reasonable estimate of the mass of a solid sphere of copper that has a diameter of 60 cm? A 0.1 kg B 10 kg C 1000 kg D 100 000 kg

The power output P of a star can be modelled with the equation P = sigma A T^4 where sigma is a constant, A is the surface area of the star and T is the surface temperature of the…

State what is meant by a vector quantity.

What represents a physical quantity? A 3.0 B kilogram C 7.0 N D 40%

The relationship between the variables D and T is given by the equation 1/T = b/sqrt(D) + c, where b and c are constants. The unit of D is m^2 and the unit of T is s. What are the…

Underline all the SI base units in the following list: ampere coulomb current kelvin newton

Which unit is not an SI base unit? A A B kg C C D s

What is the best estimate of the number of atoms in a piece of metal of volume 50 cm^3? A 5 x 10^15 B 5 x 10^25 C 5 x 10^29 D 5 x 10^31

Gm, Tm, micro-m and pm are all units of length. Which unit is the largest and which unit is the smallest? largest unit smallest unit A Gm micro-m B Gm pm C Tm micro-m D Tm pm

An aircraft travels along a horizontal path. Two of the forces that act horizontally on the aircraft are the thrust force of the engines and the force due to the wind. A vector…

What must be included in a record of a physical quantity? A an integer value for the quantity B an SI unit C a numerical value for the quantity D a unit expressed in base units

What is the ohm expressed in SI base units? A kg m^2 s^-3 A^-2 B kg^-1 m^-2 s^3 A^2 C J C^-1 A^-1 D W A^-2

The diagram shows two vectors, X and Y, drawn to scale. Vector X points up and to the left; vector Y points horizontally to the right. If X = Y - Z, which diagram represents the…

What is a reasonable estimate of the cross-sectional area of the wire in a paper clip? A 1 x 10^-3 m^2 B 8 x 10^-5 m^2 C 8 x 10^-7 m^2 D 1 x 10^-9 m^2

The diagram shows two coplanar forces, P and Q, drawn to scale. P is a horizontal arrow pointing right; Q is an arrow of similar length pointing down and to the right at an angle…

A student estimates the maximum speed of some different moving objects. Which maximum speed is not a reasonable estimate? A container ship: 10 m s^-1 B Olympic sprinter: 0.1 km…

What is the best estimate of the wavelength of green light? A 260 nm B 540 nm C 780 nm D 920 nm

In an electric circuit, an ammeter reads 2 uA. In a second circuit, the ammeter reads 1 mA. How many times larger is the current in the second circuit compared with the current in…

A boat is crossing a river in which the water is moving at a speed of 4.0 m s^-1 from left to right. In still water, the speed of the boat is 6.0 m s^-1. The boat is directed at…

Compare scalar and vector quantities.

Table 1.1 lists some physical quantities (acceleration, charge, momentum, power, upthrust). Complete the table by placing a tick next to the scalar quantities.