Aim Below Fish: Hit It With Red Laser Beam

[rasenehi]

1. If while standing on a bank you wished to zap a small blue fish out in front of you with red laser beam, would you aim above, below, or directly at the observed fish to make a direct hit?


2. Snells law : n1sin∅1=n2sin∅2

3. For visible light index of refraction decreases with wavelength, so blue light will have a smaller n then red light. Therefore, when you are looking at the fish from the bank you will see the fish above where it is and since n for red light is greater it will refract downwards at a greater angle than the blue light. Then you should aim below the fish so that you will hit it?

 

[anathema]

I would like to provide some clarification and additional information regarding this scenario. First, let's discuss the concept of Snell's law. This law describes how light bends when it passes through different materials with varying refractive indices. The refractive index is a measure of how much the speed of light is reduced when it passes through a material, and it is dependent on the wavelength of the light. This means that different colors of light will have different refractive indices when passing through the same material.

Now, let's apply this concept to the scenario at hand. If we assume that the laser beam is passing through air (which has a refractive index of 1) and then through water (which has a refractive index of 1.33), we can use Snell's law to determine the direction in which the laser beam will bend as it enters the water. As stated in the forum post, the refractive index decreases with wavelength, so blue light (with a shorter wavelength) will have a smaller refractive index than red light (with a longer wavelength).

Based on this information, we can conclude that the blue light will bend more than the red light as it enters the water, causing the fish to appear higher than its actual position. Therefore, in order to make a direct hit on the fish, you would need to aim below the fish, as the forum post suggests.

However, it is important to note that this scenario assumes a perfect and stationary target. In reality, the fish may be moving and the laser beam may not hit it directly due to factors such as the speed of the fish and the movement of the water. Additionally, other factors such as the angle at which the laser beam is emitted and the angle at which the fish is viewed can also affect the accuracy of the hit.

In conclusion, while aiming slightly below the fish would likely result in a direct hit, it is important to consider all the variables and limitations in this scenario. As scientists, we must always approach problems with a critical and analytical mindset, considering all factors and potential sources of error.