What type of malware locks a user's files and demands

Why is red colour preferred for danger signal lights?

The instrument for measuring intensity of earthquakes is called –

The Atom Bomb dropped in Nagasaki is an uncontrolled nuclear fission made up of:

A bus moving along a circular track is an example of

Which among the following is a vector quantity? 

Which statement(s) about solenoids are INCORRECT?

Which color of light experiences the most bending when it passes through a prism and separates from white light?

How much calorie of energy is released by a boiled egg?

Which lens is used in sodium reflector lamp ? 

One Kilowatt hour is equal to—