Give reasons.
A revolving stone tied in a string files away when the string breaks.

What are similarities and differences between refraction, reflection, diffraction and absorption?

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?