A beam of light strikes a mirror at angle of 23° to the normal. What is the angle between the incident and reflected beam?

well, during reflection

angle of incident is equal to angle of reflection so if angles of incident is 23° , then angle of reflection is also equal to 23° .

so the total angle between the reflected and incident ray will be equal to angle of incidence plus angle of reflection

i.e. angle i + angle r = 23° + 23° = 46°

hence the required angle is 46°

i hope it helped .

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west