What is the instrument used to measure the intensity of earthquakes called?

Which instrument is used to measure the concentration of gases in a mixture?

What is the instrument used to measure the frequency of sound waves called?

Which instrument is used to measure the angle between two objects?

What is the instrument used to measure the electric potential difference between two points called?

Which instrument is used to measure the electrical resistance of a material?

Which instrument is used to measure the velocity of a fluid?

What is the instrument used to measure the humidity in the air called?

What is the instrument used to measure the pressure exerted by a gas called?

Which instrument is used to measure the concentration of a solute in a solution?