Which instrument is used to measure the oxygen level in a gas mixture?

What is the instrument used to measure the total dissolved solids in a solution called?

Which instrument is used to measure the refractive index of transparent materials?

Which instrument is used to measure the intensity of electromagnetic radiation?

What is the instrument used to measure the force exerted by gases or liquids called?

Which instrument is used to measure the density of gases?

Which instrument is used to measure the depth of oceans?

Which instrument is used to measure the altitude of sun?

Which instrument is used to measure the blueness of sky and ocean?

Which instrument is used to measure the sensitiveness of skin?