A plane electromagnetic wave propagating in a non magnetic dielectric medium is given by E=E0sin[2×10−7x−50t], where 'x' is in meter and 't' is in second. If the relative permeability of the medium μr=1 then the dielectric constant of the medium is

Speed of electromagnetic wave in Vacuum is  C=1μ0∈0Speed of electromagnetic wave in a dielectric medium of dielectric constant (k) is given by  C'=1kμ0∈0=CkFrom given equation  C'=ωk=502×10−7C'=52×108m/s  and  C=3×108m/s Using,  C'=Ck ⇒52×108=3×108k ⇒254=9k ⇒k=1.44