Light from a laser strikes a diffraction grating that has 5500 lines per centimeter. the central and first-order maxima are separated by 0.455 m on a wall, 1.62 m from the grating, calculate the wavelength of the laser light.

.

491.4 nm

Explanation:

The distance between central and first maxima is,

And the distance between screen abnd grating is,

Now the angle can be find as,

Now the grating distance is,

Now with m=1 condition will become,

So,

Therefore the wavelength of laser light is 491.4 nm.

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