Question

Light waves travel in vacuum along the y-axis. Which of the following may represent the wave front?

• A. y = constant
• B. x = constant
• C. z = constant
• D. x + y + z = constant

Answer 1

Answer: (A)

y = constant

Answer 2

As velocity of light is perpendicular to the wavefront and light is travelling in vacuum along the $y-$ axis, therefore, the wavefront is represented by $y=$ constant.