Momentum & Radiation Pressure

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): The electromagnetic wave exerts pressure on the surface on which they are allowed to fall.

Reason (R): There is no mass associated with the electromagnetic waves.

In the light of the above statements, choose the correct answer from the options given below:

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): Electromagnetic waves carry energy but not momentum.

Reason (R): Mass of a photon is zero.

In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements:

Statement I: Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields.

Statement II: When electromagnetic waves strike a surface, a pressure is exerted on the surface. In the light of the above statements, choose the most appropriate answer from the options given below:

Average force exerted on a non-reflecting surface at normal incidence is $2.4 \times 10^{-4}\text{ N}$. If $360\text{ W/cm}^2$ is the light energy flux during span of 1 hour 30 minutes, then the area of the surface is:

An object is placed in a medium of refractive index 3. An electromagnetic wave of intensity $6 \times 10^{8}\text{ W/m}^2$ falls normally on the object and it is absorbed completely. The radiation pressure on the object would be (speed of light in free space $= 3 \times 10^{8}\text{ m/s}$):

A point source of light is placed at the centre of curvature of a hemispherical surface. The source emits a power of $24\text{ W}$. The radius of curvature of hemisphere is $10\text{ cm}$ and the inner surface is completely reflecting. The force on the hemisphere due to the light falling on it is ____________ $\times 10^{-8}\text{ N}$.

Sun light falls normally on a surface of area $36\text{ cm}^{2}$ and exerts an average force of $7.2 \times 10^{-9}\text{ N}$ within a time period of 20 minutes. Considering a case of complete absorption, the energy flux of incident light is

The electric field in a plane electromagnetic wave is given by

$\vec{E} = 200 \cos\left[\left(\frac{0.5 \times 10^{3}}{m}\right) x - \left(1.5 \times 10^{11} \frac{rad}{s} \times t\right)\right] \frac{V}{m} \hat{j}$. If this wave falls normally on a perfectly reflecting surface having an area of 100 cm2. If the radiation pressure exerted by the E.M. wave on the surface during a 10 minute exposure is $\frac{x}{10^{9}} \frac{N}{m^2}$. Find the value of x.

If 2.5 $\times$ 10$-$6 N average force is exerted by a light wave on a non-reflecting surface of 30 cm2 area during 40 minutes of time span, the energy flux of light just before it falls on the surface is ___________ W/cm2. (Round off to the Nearest Integer)

(Assume complete absorption and normal incidence conditions are there)

Light is incident normally on a completely absorbing surface with an energy flux of 25 W cm–2. If the surface has an area of 25 cm2, the momentum transferred to the surface in 40 min time duration will be:

50 W/m2 energy density of sunlight is normally incident on the surface of a solar panel. Some part of incident energy (25%) is reflected from the surface and the rest is absorbed. The force exerted on 1m2 surface area will be close to (c = 3 × 108 m/s) :-

A radiation of energy 'E' falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (C = Velocity of light)

Light with an energy flux of 25 $\times$ 104 W m${}^{-2}$ falls on a perfectly reflecting surface at normal incidence. If the surface area is 15 cm2, the average force exerted on the surface is

A radiation of energy $E$ falls normally on a perfectly reflecting surface. The momentum transferred to the surface is