Physics symbols related to mechanics, thermal physics, electricity and magnetism, practice problems, FAQs

To reduce the time to denote each term by its name, we generally introduce the symbols in science. In Physics, we use several symbols and some of them even get repeated i.e. they are sometimes used to denote different quantities. Here we will be covering some important symbols that are used in Physics. While using them in different equations we should use them appropriately. This is to ensure easy readability.

Table of contents

Physics symbols related to space and time
Physics symbols related to mechanics
Physics symbols related to thermal physics
Physics symbols related to electricity and magnetism
Practice Problems
FAQs

Physics symbols related to space and time

Quantity	Symbol	Name	Units
Length	l	-	m
Mass	m	-	kg
Time	t	-	s
Density		Rho	kg/m3
Temperature	T	-	K
Frequency	f,	Nu	Hertz (Hz)
Wavelength		Lambda	m
Angular displacement		Theta	rad
Speed of light	c	-	m/s
Angular frequency		Omega	rad/s

Physics symbols related to mechanics

Quantity	Symbol	Name	Units
Velocity	v	-	m/s
Acceleration	a	-	m/s2
Angular acceleration		Alpha	rad/s2
Momentum	p	-	kg m/s
Period	T	-	s
Force	F	-	N
Torque		Tau	Nm
Power	P	-	Watt, W
Work	W	-	Joule, J
Energy	E	-	Joule, J
Pressure	P	-	Pa
Moment of inertia	I	-	kg m2
Angular momentum	L	-	kg m2/s
Friction	f	-	N
Coefficient of friction		Mu	No unit
Kinetic Energy	K	-	Joule, J
Potential energy	U	-	Joule, J
Efficiency		Eta	No unit
Spring Constant	k	-	N/m
Stress		Sigma	N/m2 or Pa
Strain		Epsilon	No unit

Physics symbols related to thermal physics

Quantity	Symbol	Name	Units
Enthalpy	H	-	Joule, J
Entropy	S	-	J/K
Internal energy	U	-	Joule, J
Emissivity		Epsilon	No unit
Thermal conductivity	K	-	W/m K
Specific heat capacity	c	-	J/kg K
Latent heat capacity	L	-	J/kg
Heat	Q	-	Joule, J
Quantity of substance	n	-	Moles

Physics symbols related to electricity and magnetism

Quantity	Symbol	Name	Units
Charge	q	-	Coulomb (C)
Current	I	-	Ampere (A)
Resistance	R	-	Ohms ()
Inductance	L	-	Henry (H)
Capacitance	C	-	Farad (F)
Potential difference	V	-	Volt (V)
Electric field	E	-	N/C
Magnetic field	B	-	Tesla
Magnetic Flux	B	Phi	Weber
Dielectric constant		epsilon	No unit
Electric Flux	E	Phi	Nm2/C
Linear charge density		Lambda	C/m
Areal charge density		Sigma	C/m2
Volume charge density		Rho	C/m3

Practice Problems:

Q. Write the expression for work done by a force causing a displacement. Use usual symbols.

A. Work done = Force . Displacement

In usual symbols, W=F.d

Q. Write the expression for a force on a mass causing acceleration. Use usual symbols.

A. We know Force= mass . acceleration

In usual symbols, F=ma

Q. How torque can be expressed in symbols? Is its dimension the same as energy?

A. We know, Torque = Inertia . angular acceleration

In symbolic expression, = I

The dimension of torque is the same as the energy. But the main difference is that torque is a vector quantity whereas energy is a scalar quantity.

Q. Express the total charge contained in a plate in terms of the surface charge density. Express in terms of usual symbols.

A. Let the surface charge density on the plate be and the area be A

If the total charge contained is Q

Then, Q=A

FAQs

Q. What's the unit of specific enthalpy? How is it expressed ?
A. The SI unit of specific enthalpy is J/kg. The enthalpy is expressed with H and the specific enthalpy is generally expressed with ‘h’.

Q. How is the wavelength of a wave expressed? What is its unit?
A. The wavelength is generally expressed by the greek letter, . Its unit is m. For practical purposes, we express the wavelengths in mm, m, nm etc as they are units used for very small lengths.

Q. Moment of inertia is expressed by I. Angular acceleration is expressed by . How the torque will be expressed in terms of I and ?
A. We know that,

Torque is the rate of change of angular momentum.
So, torque =Moment of inertia Angular acceleration
If torque is expressed by , then = I

Q. How is capacitance expressed with a symbol? Express it with the symbols of charge and voltage.
A. Generally capacitance is expressed with the letter C. Charge is expressed with the letter Q, voltage with V

We know, Charge=Capacitance Voltage Q=CV