Question

The momentum in (k-m/s) of photon of energy 6 MeV energy is ___

Answer 1

Hint: Momentum is a vector quantity in the sense that it has both a magnitude and a direction. The time rate of shift of momentum is proportional to the force acting on the particle, according to Isaac Newton's second law of motion. Linear momentum, also known as translational momentum or simply momentum, is the product of an object's mass and velocity in Newtonian mechanics.

Complete answer:
The rate of change of a body's momentum is proportional to the net force acting on it, according to Newton's second law of motion. Momentum varies depending on the frame of reference, but it is a conserved quantity in each inertial frame, meaning that if a closed system is not influenced by external forces, the overall linear momentum remains constant. Momentum is conserved in special relativity (with a modified formula) as well as electrodynamics, quantum mechanics, quantum field theory, and general relativity (in a modified form). It is a manifestation of translational symmetry, which is one of the basic symmetries of space and time.
E = mc², an equation in Albert Einstein's special relativity principle that describes the fact that mass and energy are the same physical entity that can be changed into one another. The kinetic energy (E) of a body is proportional to its augmented relativistic mass (m) times the speed of light squared (c²) in the equation.
Given
E = 6 MeV
E = mc²
\[E = (mC) \cdot C\]
We know that P = mc
\[P = \dfrac{E}{C}\]
= \[\dfrac{{6 \times {{10}^6} \times 1.6 \times {{10}^{ - 19}}}}{{3 \times {{10}^8}}}\]
\[ = 3.2 \times {10^{ - 21}}\;{\text{kg}} - {\text{m}}/{\text{s}}\]

Note:
A momentum density can be described in continuous systems like electromagnetic fields, fluid dynamics, and deformable bodies, and a continuum version of the conservation of momentum results in equations like the Navier–Stokes equations for fluids and the Cauchy momentum equation for deformable solids or fluids.