Alightbulb has a power of 100 w and is used for 4 hours. a microwave has a power of 1200 w and is used for 5 minutes.
a) how much energy is used by the lightbulb?
b) how much energy is used by the microwave?
c) the lightbulb has an efficiency of 1.8%. how much heat energy does the lightbulb produce in 4 hours?

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.

If the specific heat of a metal is 0.850 j/g °c, what is its atomic weight?

Ultraviolet radiation is dangerous because it has a high enough energy to damage skin cells. what is the best explanation of the relationship between wavelength and wave energy? a) wave energy is related only to frequency, not wavelength. b) longer wavelengths have lower frequencies but higher energy. c) the shorter the wavelength, the lower the frequency and the higher the energy. d) the shorter the wavelength, the higher the frequency and the higher the energy.