Agemstone is a hard, colorful mineral with a glassy or shiny luster. true or false?

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f

If 2 moles of co_2 at 2l and 500k are expanded reversibly to 20l, more work can be obtained from an adiabatic process than from an isothermal process. is the above statement true or false?