In measuring the width of a hair sample, a light of wavelength 500 nm is used. the hair sample is 40 um in radius. with the screen 6 meters away from the hair sample, where would the second dark band away from the central bright spot be located?

The distance of the second dark band away from the central bright spot be located is

Explanation:

Given that,

Wave length = 500 nm

Radius

Distance from the hair sample D= 6 m

We need to calculate the distance of the second dark band away from the central bright spot be located

Using formula for dark fringe

Put the value into the formula

Hence, The distance of the second dark band away from the central bright spot be located is

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be