Consider the refractive index of free electrons in copper, at frequencies around the plasma frequency, ωp in the Drude model. Write expressions for the reflectivity R at normal incidence as a function of frequency  in the vicinity of ωp. For copper the free electron relaxation time is 1.9 x10-14 s and the plasma energy is 7.8 eV.

The expression is given in the pictures below

Explanation:

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

490 n

f=125n a=2.5m/s2