Question

A charged particle travels through a glass with index of n= 1.5 with a velocity of 0.9c. Which of the following is true

(a) The particle travels faster than the speed light in the glass and will produce a shock wave called Cherenkov radiation

(b) The particle travels slower than the speed light in the glass and will produce a shock wave called Cherenkov radiation

(c) The particle travels slower than the speed light in the glass and does not produce Cherenkov radiation

(d) The particle travels faster than the speed light in the glass and does not produce Cherenkov radiation

Answer 1

Cherenkov radiation results when the charged particles like electrons travels through dielectric materials like glass faster then the speed of light.

As mentioned in the statement is the "A charged particle travels through a glass with index n= 1.5 with a velocity 0.9c.

Hence we may conclude as follows.

(c) The particle travels slower than the speed light in the glass and does not produce Cherenkov radiation.

And the statements (a) is also correct. But from the main statement the velocity of particle is 0.9c which is lesser than speed of light c. Hence does not radiates Cherenkov.