In four regions I, II, III and IV, the magnetic field is given by: I. B_y = B_0 sin kz II. B_y = B_0 cos kz III. B_y = B_0 sin ( kz -ω t ) IV. B_y =…

In four regions I, II, III and IV, the magnetic field is given by : I. $\displaystyle \mathrm{B}_{\mathrm{y}}=\mathrm{B}_{0} \sin \mathrm{kz}$ II. $\displaystyle \mathrm{B}_{\mathrm{y}}=\mathrm{B}_{0} \cos \mathrm{kz}$ III. $\displaystyle \mathrm{B}_{\mathrm{y}}=\mathrm{B}_{0} \sin (\mathrm{kz}-\omega \mathrm{t})$ IV. $\displaystyle \mathrm{B}_{\mathrm{y}}=\mathrm{B}_{0} \sin \mathrm{kz}+\mathrm{B}_{0} \cos \mathrm{kz}$ The electromagnetic wave will exist in the region :