Question

According to Einstein’s theory, how does an increase in the number of photons affect a beam of light?
The wavelength of the beam of light increases.
The speed of the beam of light increases.
The brightness of the beam of light increases.
The frequency of the light beam increases.
The energy of each photon in the beam of light increases.

Answer 1

Answer : When the number of photons increases, the brightness of the beam of light increases.

Explanation :

According to Einstein's theory, $E=n\ h\ \nu$

Where,

n is the no of photons.

h is the Plank's constant

$\nu$ is the frequency of light.

$n=\dfrac{E}{h\nu}$

So, the number of photon depends directly on the total energy of the group of photons and inversely on the frequency.

Out of given options, the correct one can be (c) or (e). But in (e), it is written that the energy of each photon increases. This is wrong because the total energy of the photon should increase.

Hence, the correct option is (c) "The brightness of the beam of light increases".

Answer 2

Answer:

c

Explanation:

Einstein’s photons of light were individual packets of energy having many of the characteristics of particles. Recall that the collision of an electron (a particle) with a sufficiently energetic photon can eject a photoelectron from the surface of a metal. Any excess energy is transferred to the electron and is converted to the kinetic energy of the ejected electron. Einstein’s hypothesis that energy is concentrated in localized bundles, however, was in sharp contrast to the classical notion that energy is spread out uniformly in a wave. We now describe Einstein’s theory of the relationship between energy and mass, a theory that others built on to develop our current model of the atom.

(well ====  the other person did real math unlike me)