Physical Quantities, Symbols and Units

Table 1 below indicates the physical quantities required for numerical calculations that are included in the Access 3 Physics units and the Intermediate 1 Physics units and course together with the SI unit of the quantity.

Table 1

Physical Quantity	Unit
distance	metre
time	second
speed, average speed	metre per second
mass	kilogram
weight	newton
current	ampere
voltage	volt
resistance	ohm
power	watt
input voltage	volt
output voltage	volt
voltage gain	-

Table 2 below indicates the physical quantities required for numerical calculations that are included in the Standard Grade Physics course together with:

• the symbol used by SQA

• the SI unit of the quantity (and alternative units included in the course)

• the abbreviation for the unit used in Credit level examinations.

In General level examinations full words are used for the units of all physical quantities.

Table 2

Physical Quantity	Symbol			Unit	Unit
					Abbreviation
distance	d or s			metre	m
				light year
height		h		metre	m
wavelength		λ		metre	m
amplitude	Α			metre	m
time		t		second	s
speed, final speed		v		metre per second	m/s
initial speed		u		metre per second	m/s
change of speed	∆v			metre per second	m/s
average speed				metre per second	m/s
		v
frequency		f		hertz	Hz
acceleration		a		metre per second per second	m/s2
acceleration due to gravity		g		metre per second per second	m/s2
gravitational field strength		g		newton per kilogram	N/kg
mass	m			kilogram	kg
weight	W			newton	N
force, thrust	F			newton	N
energy	E			joule	J
				kilowatt-hour	kW h
kinetic energy	Ek			joule	J
potential energy	Ep			joule	J
heat energy	Eh			joule	J
input energy	Ei			joule	J
output energy	Eo			joule	J
work done	W or EW			joule	J
power	P			watt	W

Physical Quantity	Symbol	Unit	Unit
			Abbreviation
output power	Po	watt	W
input power	Pi	watt	W
focal length of a lens	f	metre	m
power of a lens	P	dioptre	D
electric charge	Q	coulomb	C
electric current	I	ampere	A
voltage	V	volt	V
resistance	R	ohm	Ω
input voltage	Vi	volt	V
output voltage	Vo	volt	V
voltage gain	Ao or Vgain	-	-
power gain	Pgain	-	-
primary voltage	Vp	volt	V
secondary voltage	Vs	volt	V
primary current	Ip	ampere	A
secondary current	Is	ampere	A
number of turns on primary	np	-	-
coil
number of turns on secondary	ns	-	-
coil
efficiency	(η)	-	-
temperature	T	degree Celsius	°C
specific heat capacity	c	joule per kilogram per	J/kg °C
		degree Celsius
specific latent heat	l	joule per kilogram	J/kg
activity	A	becquerel	Bq
count rate	-	counts per second	-
		(counts per minute)
equivalent dose	H	sievert	Sv
half-life	t½	second	s
		(minute, hour, day, year)

Table 3 below indicates the physical quantities required for numerical calculations that are included in the Intermediate 2 Physics course together with:

• the symbol used by SQA

• the SI unit of the quantity (and alternative units included in the course)

• the abbreviation for the unit used in Intermediate 2 examinations.

Table 3

Physical Quantity	Symbol			Unit	Unit
					Abbreviation
distance	s or d			metre	m
displacement		s		metre	m
speed, velocity		v		metre per second	m/s
time		t		second	s
change of velocity	∆v			metre per second	m/s
average velocity				metre per second	m/s
		v
initial velocity		u		metre per second	m/s
final velocity		v		metre per second	m/s
acceleration		a		metre per second per second	m/s2
mass	m			kilogram	kg
weight	W			newton	N
force	F			newton	N
acceleration due to gravity		g		metre per second per second	m/s2
gravitational field strength		g		newton per kilogram	N/kg
momentum		p		kilogram metre per second	kg m/s
energy	E			joule	J
work done	W or EW			joule	J
potential energy	Ep			joule	J
height		h		metre	m
kinetic energy	Ek			joule	J
power	P			watt	W
efficiency	(η)			-	-
temperature		T		degree Celsius	°C
specific heat capacity		c		joule per kilogram per degree	J/kg ˚C
				Celcius
specific latent heat		l		joule per kilogram	J/kg
heat energy	Eh			joule	J

Physical Quantity	Symbol	Unit	Unit
			Abbreviation
electric charge	Q	coulomb	C
electric current	I	ampere	A
voltage, potential difference	V	volt	V
supply voltage	Vs	volt	V
resistance	R	ohm	Ω
total resistance	RT	ohm	Ω
number of turns on primary	np	-	-
coil
number of turns on secondary	ns	-	-
coil
primary voltage	Vp	volt	V
secondary voltage	Vs	volt	V
primary current	Ip	ampere	A
secondary current	Is	ampere	A
input voltage	Vi	volt	V
output voltage	Vo	volt	V
voltage gain	Ao or Vgain	-	-
wavelength	λ	metre	m
frequency	f	hertz	Hz
period	T	second	s
amplitude	A	metre	m
angle	θ	degree	°
critical angle	θc	degree	°
power (of a lens)	P	dioptre	D
focal length	f	metre	m
activity	A	becquerel	Bq
count rate	-	counts per second	-
		(counts per minute)
absorbed dose	D	gray	Gy
radiation weighting factor	wR	-	-
equivalent dose	H	sievert	Sv
half-life	t½	second	s
		(minute, hour, day, year)

Table 4 below indicates the physical quantities required for numerical calculations that are included in the Higher Physics course together with:

• the symbol used by SQA

• the SI unit of the quantity (and alternative units included in the course)

• the abbreviation for the unit used in Higher examinations.

Table 4

Physical Quantity	Symbol			Unit	Unit
					Abbreviation
distance	s or d			metre	m
displacement		s		metre	m
speed, velocity		v		metre per second	m s-1
time		t		second	s
change of velocity	∆v			metre per second	m s-1
average velocity				metre per second	m s-1
		v
final velocity		v		metre per second	m s-1
initial velocity		u		metre per second	m s-1
acceleration		a		metre per second per second	m s-2
mass	m			kilogram	kg
weight	W			newton	N
acceleration due to gravity		g		metre per second per second	m s-2
gravitational field strength		g		newton per kilogram	N kg-1
force, tension, upthrust	F			newton	N
momentum		p		kilogram metre per second	kg m s-1
impulse	(∆p)			newton second	N s
				kilogram metre per second	kg m s-1
energy	E			joule	J
work done	W or EW			joule	J
potential energy	Ep			joule	J
height, depth		h		metre	m
kinetic energy	Ek			joule	J
power	P			watt	W
volume	V			cubic metre	m3
density		ρ		kilogram per cubic metre	kg m-3
area	A			square metre	m2
pressure	P or p			pascal	Pa
temperature		T		kelvin	K
				degree Celsius	°C

Physical Quantity	Symbol	Unit	Unit
			Abbreviation
electric charge	Q	coulomb	C
electric current	I	ampere	A
voltage, potential difference	V	volt	V
electromotive force (e.m.f)	E or ε	volt	V
internal resistance	r	ohm	Ω
resistance	R	ohm	Ω
peak voltage	Vpeak	volt	V
root mean square voltage	Vrms	volt	V
peak current	Ipeak	ampere	A
root mean square current	Irms	ampere	A
capacitance	C	farad	F
input voltage	V1 or V2	volt	V
output voltage	Vo	volt	V
feedback resistance	Rf	ohm	Ω
voltage gain	Ao or Vgain	-	-
period	T	second	s
frequency	f	hertz	Hz
wavelength	λ	metre	m
angle	θ	degree	°
critical angle	θc	degree	°
refractive index	n	-	-
irradiance	I	watt per square metre	W m-2
Planck’s constant	h	joule second	J s
number of photons per second	N	-	-
threshold frequency	fo	hertz	Hz
energy level	W1, W2, …	joule	J
speed of light in a vacuum	c	metre per second	m s-1
activity	A	becquerel	Bq
count rate	-	counts per second	-
		(counts per minute)
number of nuclei decaying in	N	-	-
time t
absorbed dose	D	gray	Gy

Physical Quantity	Symbol	Unit	Unit
			Abbreviation
absorbed dose rate	&	gray per second	Gy s-1
	D	gray per hour	Gy h-1
		gray per year	Gy y-1
radiation weighting factor	wR	-	-
equivalent dose	H	sievert	Sv
equivalent dose rate	&	sievert per second	Sv s-1
	H	sievert per hour	Sv h-1
		sievert per year	Sv y-1
effective dose	H	sievert	Sv
half-life	t½	second	s
		(minute, hour, day, year)
half-value thickness	T½	metre	m

Table 5 below indicates the physical quantities required for numerical calculations that are included in the Advanced Higher Physics course together with:

• the symbol used by SQA

• the SI unit of the quantity (and alternative units included in the course)

• the abbreviation for the unit used in Advanced Higher examinations.

Table 5

Physical Quantity	Symbol	Unit	Unit
			Abbreviation
distance, depth, height	d or h	metre	m
displacement	s or x or y	metre	m
length	l	metre	m
radius	r	metre	m
time	t	second	s
initial velocity	u	metre per second	m s-1
speed, velocity, final velocity	v	metre per second	m s-1
acceleration	a	metre per second per second	m s-2
mass	m	kilogram	kg
rest mass	mo	kilogram	kg
energy	E	joule	J
speed of light in a vacuum	c	metre per second	m s-1
angular displacement	θ	radian	rad
initial angular velocity	ω	radian per second	rad s-1
	o
angular velocity,	ω	radian per second	rad s-1
final angular velocity
angular acceleration	α	radian per second per second	rad s-2
tangential acceleration	at	metre per second per second	m s-2
radial acceleration	ar	metre per second per second	m s-2
force	F	newton	N
torque	Τ	newton metre	N m
moment of inertia	I	kilogram metre squared	kg m2
angular momentum	L	kilogram metre squared per	kg m2 s-1
		second
rotational kinetic energy	Erot	joule	J
gravitational field strength	g	newton per kilogram	N kg-1
gravitational potential	U or V	joule per kilogram	J kg-1
gravitational potential energy	Ep	joule	J
amplitude	Α	metre	m
angular frequency	ω	(radian per second)	(rad s-1)

Physical Quantity	Symbol	Unit	Unit
			Abbreviation
wavelength	λ	metre	m
momentum	p	kilogram metre per second	kg m s-1
electric charge	Q or q	coulomb	C
electric field strength	E	newton per coulomb	N C-1
electrical potential	V	volt	V
potential difference	V	volt	V
electric current	I	ampere	A
magnetic induction	B	tesla	T
angle	θ	degree	˚
		radian	rad
induced e.m.f.	E or ε	volt	V
self-inductance	L	henry	H
frequency	f	hertz	Hz
period	T	second	s
velocity of source	vs	metre per second	m s-1
velocity of observer	vo	metre per second	m s-1
frequency of source	fs	hertz	Hz
phase angle	Φ	radian	rad
refractive index	n	-	-
fringe separation	∆x	metre	m
slit separation	d	metre	m
grating to screen distance	D	metre	m
polarising angle	ip	degree	˚
(Brewster’s angle)