# raidation interacts with matter 6.2 AS SaltersWatch

#1
you want to heat up a cup of cffee in a micriowave cooker. The cooker uses radiation of frequency 2.45*10^9 HZ
The cup contains 150cm^3 of coffee which is mainly water

a)use the data on the mass, temperature rise and specific heat capacity of water to calculate the energy needed to raise the temperature of the water by 30celsius

b) how much energy is transferred to the water by each photon of microwave radiation

Can anyone explain how to do these 2? Is there a formula, I have the answers already I want to know how you get to them.
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9 years ago
#2
q=mc(delta)t for part 1.

Then plancks equation for part 2, E=fv i think.
EDIT: Post again if still stuck.
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#3
I did c*m*delta t for the first one
150*30*4.18 and got 18810 but the answers say it should be 1.89*10^4

and for b) it says the answer is 1.62 * 10^-24j
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9 years ago
#4
(Original post by f45)
I did c*m*delta t for the first one
150*30*4.18 and got 18810 but the answers say it should be 1.89*10^4

and for b) it says the answer is 1.62 * 10^-24j

EDIT: For b) just plug the given frequency and plancks constant into E=fv... 6.6^-34*2.45^9 = 1.62^-24~
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#5
Oh ok thank you
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