Suppose which a x-ray deviation has a wavelength of 12.4cm . How most photons have been compulsory to feverishness 265mL of coffee from 25.0C to 62.0C ? Assume which a coffee has a same density, 0.997g/mL , as well as specific feverishness capacity, 4.184J/(g*K) , as H2O over this heat range.
can any one assistance with this?
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The enthalpy needed to raise the temperature of the coffee is:
∆H = mc∆T = (265 ml) (0.997 g/mL) (4.184J/g*K) (62.0 °C – 25.0 °C) = 40,900 J.
The energy of a single photon of microwave radiation is:
E = hc/λ = (6.63×10^-34 J*s) (3.00×10^8 m/s) / (0.124 m) = 1.60×10^-24 J/photon.
Therefore:
(40,900 J) / (1.60×10^-24 J/photon) = 2.55×10^28 photons
are needed to heat the coffee.