Questions

Fathometer is used to measure Ocean depth.

Fathometer is A depth finder that uses sound waves to determine the depth of water.

The Richter Scale is used to measure the intensity of Earthquakes.

The Decibel Scale is used to measure sound intensity.

Wrought Iron is the purest form of iron. It contains 0.12 to 0.25% carbon and so it is the purest form of iron.

Angle traced by hour hand in 12 hrs = 360º.

Angle traced by hour hand in 5 hrs 10 min.  i.e., 31/6 hrs = 36012*316°= 155º

Fats are to be under macronutrients.

An operating system is the system software that handles the software and hardware resources and provides services for the computer programs. SO without an operating system, a computer cannot "boot".

The working principle of a washing machine is centrifugation.

Centrifugation is a separation process which uses the action of centrifugal force to promote accelerated settling of particles in a solid-liquid mixture.

The washing machine consists of centrifuge for this purpose. A centrifuge is a piece of equipment that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis of spin that can be very strong.

The relative pronoun acts as the subject or object of the relative clause. It replaces words like she, he, him, her, they, them etc.

It is, therefore, wrong to repeat the pronoun in the relative clause.

Hence, the correct sentence is Shreya, who is my best friend, is a singer.