How much energy in joules (j) would an electric heater that draws 9.5 a when connected to a 120 v supply use if the heater were allowed to run for 2 hours.

Explanation:

Energy = Power x Time

Power = Voltage x Current

Voltage = 120 V

Current = 9.5 A

Power = Voltage x Current

Power = 120 x 9.5 = 1140 W

Time = 2 hours = 2 x 60 x 60 = 7200 s

Energy = Power x Time

Energy = 1140 x 7200

Energy = 8208000 J

Energy used by heater is 8.21 x 10⁶ J

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