Q.
Electromagnetic waves travel in a medium with a speed of 2×108m/s . If the relative permeability of the medium is 1 the relative permittvity will be
Given, speed of EM wave =2×108m/s- μr=1 εr=?
The velocity or speed of EM wave in the medium, v=μrεr1×μ0ε01 We have, c=μ0ε01
where μ0 and ε0 are permeability and permittivity of
vacuum respectively. ∴v=μrεr1⋅c 3×1082×108=μrεr1[∵C=3×108ms] 32=μrεr1 (32)2=μrεr1=1×εr1
Permittivity, εr=49=2.25