Correct Answer - Option 4 : Udometer : Rain
A seismograph is an instrument is used to detect and record the Earthquakes
A rain gauge also known as an udometer is used to gather and measure the amount of liquid precipitation over an area in a predefined area, period of time.
Hence, the correct answer is "Udometer : Rain".
||Depth of Ocean
Students often get confused between Hygrometer and Hydrometer.
Hygrometer is used to measure Humidity whereas Hydrometer measures Relative Density.