Understanding Refraction
Refraction is the bending of a wave as it passes from one medium to another. This happens because the speed of the wave changes as it enters the new medium. The change in speed causes the wave to change direction.
Why No Bending at 90 Degrees
* No Change in Path Length: When a wave enters a new medium at 90 degrees, the path of the wave doesn't change in terms of its distance traveled within the new medium. It's like the wave is entering straight in, not at an angle.
* Equal Time: The time it takes for the wave to travel a specific distance in the first medium is the same as the time it takes to travel the same distance in the second medium (assuming the wavefront is perpendicular to the interface). There's no difference in speed that would lead to a change in direction.
Analogy
Imagine a car driving straight onto a different surface, like driving from pavement onto grass. If the car enters perfectly perpendicular to the edge of the grass, it doesn't change direction. However, if it enters at an angle, the wheels on one side will encounter the grass first, slowing down, while the wheels on the other side are still on pavement, causing the car to turn.
Key Points
* Refraction occurs due to a change in wave speed.
* At a 90-degree angle, the path of the wave doesn't change within the new medium, so there's no change in speed, and thus no refraction.
Let me know if you have any more questions about refraction or wave behavior!
