Home » Posts tagged 'number'

Tag Archives: number

Wave particle duality

Let n and m denote the number of photons emitted by a red and blue bulb respectively of equal power in a given time.Is n=m?



The energy of a photon is hν

where ν is the frequency.

Power = energy/time

==> nhν1 = mhν2

==> nν1 = mν2

clearly n not equal to m

Answers are delayed, be patient please!

Dear users, visitors and members of askphysics,

AskPhysics is now experiencing the adverse effects of popularity. The number of questions we receive has far exceeded the number of questions we can answer. So, naturally, it takes some time to post the answers. Please bear with us. Though with a delay, we will be posting the answers.

It has come to our notice that many visitors are posting question which are not at all related to Physics or at least science in general. They are posting questions like “When will I marry?” “Will I be able to marry my lover?” and some questions of that sort. Please note that we do not pay a heed to such questions. And further, the questions posted by you never go directly to the site, but they come to the admin’s email and it is up to the admin to decide what to do with the email he receives.

The purpose of askphysics is to try to answer questions which the students generally do not ask in public. *(Please try to see the category “interesting questions, for example”). But, students are now using the system for obtaining the answers to the questions which they get as home work in school or college. We welcome the move, but you have to bear with the time delay.

Wish you all a happy time with askphysics.


Frequency of sound and loudness

What is meant by frequency? Does the loudness of sound increase with frequency?

( Thiruveni Nainar asked this question)


As you know, sound is produced by the vibrations of the sounding body. Frequency of the sound produced by the vibrations of a body is same as the frequency with which the body vibrates, i.e; the no. of vibrations completed by the body in one second.

Frequency of sound is defined as the number of vibrations completed by the sounding body per second or the number of waves crossing any point in the medium per second.

Loudness is not directly related to frequency; loudness of sound depends on the amplitude (The maximum displacement of the particles of the medium or that of the sounding body from mean position) of vibration

Confusion with the definition of unit of time and distance.

Ram Kishore Bajpai asked: (The question is posted as such without rectifying errors.)

“Why is the time defined by distance traveled by light in vacuum 1/299,452,758?
Why does the people use a easier number such as 1/300,000,000? Why didn’t 1 second?”



It seems that you are confused a little.

The distance traveled by light in vacuum in 1/299,452,758 of a second is defined as one metre. This is because light travels 299,452,758 m in one second in vacuum.

The value 299,452,758 m/s is the speed of light calculated by various experiments and universally accepted standard.

But ordinary situations do not demand this much level of accuracy. If you correct the value 299,452,758 m/s to 1 decimal accuracy, you will get 3.0 x 108 m/s  (3,00,000 m/s) and is used in ordinary calculations requiring one or two decimal places accuracy.

Questions from Properties of gases

Senarita asked:

we know that temperature has a properties to make some thing bigger in volume.we say that gas has no particular volume or shape.where we place a gas it takes the shape of that container.my question is- a gas of mass ‘m’ has a particular number of atoms or molecules.if the gas is not getting any temperature then how it is occupying all the volume of a bigger container.i mean how the inner space of two atoms or two molecules of that particular gas is increasing when i am transferring it to a bigger container.(say,every condition is constant.nothing is changed.)please answer me.

“can you give me some name of sites where i can get explanations on hydrostatics or the topics of physics.i am now in class 11.”

Master will be answering the question shortly. The visitors are requested to respond

Hits so far @ AskPhysics

  • 2,266,429 hits

Subscribe to AskPhysics via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 4,339 other subscribers

March 2021

Schrodinger’s Cat in Daily Life

%d bloggers like this: