Skip to main content

Why light has momentum (simplest and clearest explanation)


Why light have momentum even if photons are massless

Why light has momentum if photons are massless


This is because momentum is a property by which an object can influence other object’s motion, and light can do that so it has momentum


Another reason for this is even if light has zero rest mass but it does have an energy and this energy will also correspond to an equivalent mass, this mass works as momentum

There is a lot of confusion in people’s mind regarding momentum because:

It is generally taught that

P=mv

Where, P = momentum, m = mass and v = velocity of an object

This formula is not completely wrong, but it's not completely correct as well, because it's incomplete

In the complete formula for momentum:

Momentum not only depends on the mass of an object, but also on the total energy of that object

In other words, there are 2 things which are responsible for the momentum of an object:

1-     It's mass

2-     Its energy

This means that even if the mass of an object is zero, but it has some energy, it will definitely have some momentum

In the case of light all of its momentum comes from its energy

   Can you visualize light’s momentum?

The physical significance of momentum is: how an object’s motion influences other object’s motion

Light can influence an object’s motion

Sounds counterintuitive right?

This is true, but to see this on a significant scale we need to have an extremely powerful LASER

To have an idea consider this:

We would need LASER having energy equivalent to entire united state’s energy needs for one year to move only a paper pin at 10% of the speed of light

Light is able to do all this

Another example to see light’s momentum in action is laser cooling

The term LASER brings a thought that it can make objects hot, but that’s not always true, here’s how LASER can cool objects

1-     the temperature of a substance is a measure of the kinetic energy of its particles

2-     The more energy these particles have the more is the temperature

3-     What a LASER does is that it imparts its momentum to the particles of the substance

4-     This, in turn, slows down the particles, decreasing their kinetic energy, which decreases its temperature

This same cooling technique was used to from exotic matter at the international space station 

conclusion-

light can have momentum even without having mass, and this is because momentum is a combination of energy and mass, even if the mass is zero, energy will contribute to the momentum 

light's momentum can be visualized in cooling techniques using LASER

Comments

Popular posts from this blog

quantum computers explained simply (complete guide)

   Quantum computers, this a term which you probably have heard at some point, even if you are not much into technology this computing is probably the future of mankind In this article, we will be covering the following topics Do quantum computers exist? yes they exist, but they are not very powerful  Quantum computers are now a thing of reality, but the existing quantum computers are at the very initial phase of development, the current quantum computers are the ones born right after theory  Leading technology companies such as IBM and Google have been constantly researching on quantum computing and now they have successfully developed quantum computers which are able to solve certain problems At the end of this article we will also link you to the IBM’s quantum com[puter experience, so you yourself can actually experience the technology of future There is even a company that sells quantum computers, called D-Wave  D-Wave  quantum computers  a compute...

transistor

Transistors are present almost every electronic equipment that you come across in your day to day life There are nearly 100 million transistors in a mobile phone and nearly over 1 billion transistors are present on a laptop or a personal computer in this article, we will be dealing with the following topics what is transistor science of semiconductors n-type doping p-type doping working of a transistor transistor as a switch transistor as an amplifier  What is transistor Transistors in its simplest form can be thought off as a switch with special features The mechanical switch can control the flow of electric current and can be turned on and off Likewise, the same thing can be done with a transistor Unlike a mechanical switch, a transistor does not have any moving parts, does not need any human operator and can operate at a very fast rate Transistors are do all this because of the advancements in the science of semiconductors Science o...

Linux (everything)

In this article, you will get to know what is Linux , what are its applications, and 10 ways in which  Linux  is better than its competitors. If you have been wanting an operating system with a lot of stability and performance and privacy, the answer to all these questions is Linux based operating systems So let’s start by understanding what exactly is Linux What is Linux What is   Linux ? ,  Linux  is a family of open-source operating systems based on  Linux  kernel, such as Ubuntu, android,  Kali Linux , etc. A kernel is a part of an operating system which can control anything in the system, kernel helps in providing a link between hardware and software A kernel can control how much ram can an application use, how what permissions are given to an application and everything an application wants from the hardware is in the control of the kernel. For example- a camera application wants permission to access the...