Which richter magnitude range can be recorded by instruments but isn't felt? a. less than 2.9 b. 3.0 – 4.9 c. 5.0 – 5.9 d. 6.0 and higher

A. anything less than 3.0 magnitude on a richters scale usually can't be felt by humans but instruments can pick it up.

A. Less than 2.9

Explanation:

Richter scale is a measure of the intensity of the earthquakes designed and developed by Charles Richter in 1935. Its value ranges from 1.0 to 9.0 and greater. The earthquakes having a Richter magnitude of less than 2.9 are minor earthquakes which are slightly felt by a few humans but can be recorded on a seismograph. Earthquakes with magnitude above 2.9 can easily be felt by humans.

they should be similar or the same

e/c, where e is its total energy