RRB Group-D Model Paper 16 with answers for online practice

• An altimeter is an instrument used to measure altitudes in aircraft.
• The altimeter was invented by Louis Paul Cailletet.
• The measurement of altitude using altimeter is called altimetry.
• Actinometer is the instrument used to measure the heating power of radiation.
• Ceilometer is the instrument used to measure the aerosol concentration within the atmosphere.
• The accelerometer is the instrument used to measure the acceleration forces.

Important instruments and their uses -