What is the process by which a solid changes directly into a gas without passing through the liquid phase?

Which phenomenon occurs when light bends around the edges of an obstacle or aperture?

What type of lens is thicker at the centre than at the edges?

What is the SI unit of frequency?

Which colour of visible light has the longest wavelength?

Which law of thermodynamics states that heat naturally flows from a hotter body to a cooler body?

Which colour of visible light has the shortest wavelength?

Which law of thermodynamics states that energy cannot be created or destroyed only converted from one form to another?

What is the formula for kinetic energy?

What is the unit of power in the SI system?

What is the formula for gravitational potential energy?