Physics Measuring Instruments

A lactometer is a specialized instrument used to measure the density and purity of milk. It works on the principle of buoyancy and helps determine if milk has been adulterated with water or other substances.

An ammeter is specifically designed to measure electric current in a circuit. It is connected in series with the circuit component and measures the flow of electric charge in amperes.

A lactometer is a specialized hygrometer used to measure the density and purity of milk. Barometers measure atmospheric pressure, manometers measure pressure of fluids, and thermoscopes detect temperature changes.

A seismograph is the scientific instrument designed specifically to detect and record seismic waves produced by earthquakes. It consists of a sensor that detects ground motion and a recording system that produces a seismogram, showing the timing and intensity of the seismic waves.

A barometer is the meteorological instrument used to measure atmospheric pressure. It works by balancing the weight of mercury in a glass tube against the atmospheric pressure, or through aneroid mechanisms using a metal cell that expands and contracts with pressure changes.

An altimeter is specifically designed to measure altitude, which is the height above sea level or ground level. Voltmeter measures voltage, ammeter measures electric current, and barometer measures atmospheric pressure. The correct answer is A because an altimeter is the only instrument among the options that measures altitude.

A calorimeter is the instrument used to measure the amount of heat absorbed or released in a chemical reaction or physical process. Hygrometer measures humidity, megaphone amplifies sound, and neither is used for heat measurement. The correct answer is B because calorimeters are specifically designed for thermal measurements.

The abacus is one of the oldest known calculating devices, dating back to ancient civilizations around 3000 BCE. It consists of beads on rods used for arithmetic calculations. The arithmometer came much later (19th century), and 'ready reckoner' refers to printed calculation tables, not a physical device.

An altimeter is a modified barometer that measures atmospheric pressure to determine altitude. As altitude increases, atmospheric pressure decreases, and the altimeter converts this pressure difference into height readings for aviation and mountaineering.

A hygrometer measures relative humidity - the amount of water vapor in air relative to the maximum it can hold at that temperature. Atmospheric pressure is measured by a barometer, not a hygrometer.

A sling psychrometer measures relative humidity using two thermometers - one dry bulb and one wet bulb. The difference in readings allows calculation of relative humidity through evaporation cooling.

A sphygmomanometer is the medical instrument used to measure blood pressure. It consists of an inflatable cuff and a mercury or aneroid manometer. Pyrometers measure high temperatures, manometers measure pressure differences, and hygrometers measure humidity.

ILS (Instrument Landing System) is a precision approach aid for landing, not a general navigation system like GPS, VOR, or ADF. Navigation aids help determine position/course, while ILS specifically guides final approach alignment and glideslope.

A compass is a navigational instrument that uses a magnetized needle free to rotate to align with Earth's magnetic field, always pointing north-south. This makes it essential for finding directions. Bar magnets don't indicate direction, statues don't have magnetic properties for navigation, and a plain needle without magnetization won't show direction.

It measures the destructive energy of an earthquake.