$A$ linearly polarized electromagnetic wave in vacuum is given by $E = 3.1 \cos \left[(1.8)z - (5.4 \times 10^6)t\right] \hat{i} \text{ N/C}$. It is incident normally on a perfectly reflecting wall at $z = a$. Choose the correct option.

• A
  The wavelength is $5.4 \text{ m}$.
• B
  The frequency of the electromagnetic wave is $54 \times 10^4 \text{ Hz}$.
• C
  The transmitted wave will be $3.1 \cos \left[(1.8)z - (5.4 \times 10^6)t\right] \hat{i} \text{ N/C}$.
• D
  The reflected wave will be $3.1 \cos \left[(1.8)z + (5.4 \times 10^6)t\right] \hat{i} \text{ N/C}$.