A machine with an efficiency of 20% takes in 1,000J of input energy and outputs *
200 Watts of power
2,000 Joules of useful work
O 200 Joules of waste
200 Newtons of force
200 Joules of useful work
5,000 Joules of useful work
Help please

gravity

explanation:

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m