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# Tag Archives: particle

## 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?

Answer:

No

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**

## Kinematics Numerical Problems

The velocity m, v m/s, of a particle is a straight line is given by

v = 6+pt+qt³

where t is the time in seconds after the particle passes through a fixed point O.

Given that t=2 s the distance of the particle from O is 16 m and its acceleration is 32m/s², calculate

a) the value of p and of q

b) the velocity of the particle at the instant when did acceleration is zero

## Recent Research Publications in Physics

The absolute scale of neutrino masses is very important for understanding the evolution and the structure formation of the Universe as well as for nuclear and particle physics beyond the present standard model.

Elastic Scattering of He at the surface of liquid helium

Elastic scattering of ^{4}He atoms when they approach the surface of ^{4}He liquid, has been studied. The liquid surface is assumed to be uniform and the density profile is the same along and perpendicular to the surface. The incident ^{4}He atom will interact with a large number of ^{4}He atoms in the liquid near the surface of liquid ^{4}He. Hence, the effective interaction of the incident particle will be due to many-body forces.

## Question from Beats (Waves)

Sanjeet asked:

"the displacement of a particle in periodic motion is given by "y=(cos2t-2cost+2sin^2t+1). What is the no. of beats that can be heard in 10 seconds?"

## A Question from Electromagnetic Waves

Rajat asked: –

we know that electric and magnetic field are associated with charged particle but when light travells,it produces electric and magnetic field both but it consests of photons,which is a uncharged particle.why it did so?

Master will soon answer this.

By the time, if any visitor wants to answer, please use the commenting system

## Force on a charged particle

What is the force experienced by a charged particle moving perpendicular to an electric field? I understand that when it is moving parallel to the electric field, it accelerates.

(Shrishti asked)

Answer:

When a charged particle is at rest in an electric field, it experiences a force in the direction of electric field (if it is a positive charge)

If it is moving in the direction of electric field, it will be accelerated.

If it is moving opposite to the electric field, it will be decelerated.

If it is moving perpendicular to the electric field, its trajectory will be a parabola, similar to that of a horizontal projectile

## de Broglie Wavelength

**Alpha particle and a proton are accelerated from rest by the same potential. Find the ratio of their de- broglie wavelength**

(Asked by Amritha)

**Answer**:

Charge of alpha particle = 2e

Mass of alpha particle = 4 u

Charge of proton = e

mass of proton = u

The energy acquired by proton when accelerated through a pd of V,

E=eV

The momentum acquired by proton=

The de Broglie wavelength is given by

Therefore, de Broglie wavelength of Proton,

Similarly,