"Suppose a horizontal laser beam is reflected off a plane mirror that is perfectly smooth and flat. At first, the mirror is angled upward at 4 degrees, measured from the vertical. Then, the angle of the mirror is changed to 6 degrees upward. How would the angle formed by the incoming laser beam and the reflected laser beam change

The angle in between changed from 8 to 12 degrees

Explanation:

Solution:-

Angle between the incoming and reflected beam is always twice that of the inclination of the mirror.

Initially, Inclination angle θ = 4 degrees

             Angle between incident and reflected beam is twice of the inclination of mirror. Hence,

            Φ = 2*θ = 2*4 = 8 degrees.

Change, Inclination angle θ = 6 degrees

             Angle between incident and reflected beam is twice of the inclination of mirror. Hence,

            Φ = 2*θ = 2*6 = 12 degrees.

- The angle formed by the incoming laser beam and the reflected laser beam will change from 8 degrees to 12 degrees.

3. dark matter

empty space could also be a simple vacuum