Question

If `c` is the speed of electromagnetic waves in vacuum, its speed in a medium of dielectric `K` and relative permeability `mu_(r)` is
A. `v=(1)/(sqrt(mu_(r)K)`
B. `v=c sqrt(mu_(r)K)`
C. `v=(c)/(sqrt(mu_(r)K)`
D. `v=(K)/(sqrt(mu_(r)C)`

Answer 1

Correct Answer - c
Speed of light in vacuum `c=(1)/(sqrt(mu_(0)epsilon_(0)` and in another medium `v=(1)/(sqrt(mu epsilon)`
`:.(c)/(v)=sqrt((mu epsilon)/(mu_(0)epsilon_(0)))=sqrt(mu_(r)K) rArr v=(c)/(sqrt(mu_(r)K))`