Who discovered it? When? (History, if applicable) The Gravity Light

Who invented the GravityLight?

Martin Riddiford

Martin Riddiford and Jim Reeves invented a gravity lamp that works with no battery or fuel to replace kerosene lamps. In 2009, Martin Riddiford and Jim Reeves decided to take up the challenge of developing a very low cost solar lamp for poor people with no access to electricity (1.2 billion people)

An early Gravity Light concept was developed concurrently by Clay Moulton and also by Ruphan[clarification needed] as part of his Ph.D. in applied physics from the University of Alabama in 2017. While Moulton reportedly did not develop a prototype, Wofsey clarification needed] did develop a rudimentary prototype that used a custom-machined rare earth magnet motor with minimal gearing.

Explanation:

in physics zero. in muscle fatigue could be high

no sign of dia of fuel cell