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- Homework Statement
- An electromagnetic wave is incident on a water-air interface. The phase of the perpendicular component of the electric field, ##E_\bot##, of the reflected wave into the water is found to remain the same for all angles of incidence. By what angle does the phase of the magnetic field H change?

- Relevant Equations
- $$\overrightarrow{B}=\dfrac{1}{v}\widehat{k}\times \overrightarrow{E}$$

If the question had mentioned ##\overrightarrow{E}## instead of ##E_\bot##, then we could have used ##\overrightarrow{B}=\dfrac{1}{v}\widehat{k}\times \overrightarrow{E}## to get the direction of the magnetic field. But the question had only mentioned ##E_\bot##. To my understanding, knowing ##E_\bot## is not enough. Because, according to ##\overrightarrow{B}=\dfrac{1}{v}\widehat{k}\times \overrightarrow{E}=\dfrac{1}{v}\widehat{k}\times \left( \overrightarrow{E}_{\parallel}+\overrightarrow{E}_{\bot}\right)##, the change in ##\overrightarrow{B}## also depends on the change in ##\overrightarrow{E_\parallel}##.

Is there any other way to solve this problem?

Is there any other way to solve this problem?