# Chem 4 A - Ans Okk I know the formula is lamda=h/mu Where m...

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4. Only a fraction of the electric energy supplied to a tungsten lightbulb is converted to visible light. The rest of the energy shows up as infrared (that is, heat). A 60.0-W lightbulb converts 15.0 percent of the energy supplied to it into visible light (assume wavelength to be 565 nm). How many photons are emitted by the lightbulb per second (1 W= 1 J/s)? 8. Thermal neutrons are neutrons that move at speeds comparable to those of air molecules at room temperature. These neutrons are most effective in initiating a nuclear chain reaction among 235U isotopes. Calculate the wavelength (in nm) associated with a beam of neutrons moving at 7.08*1062 m/s (mass of a neutron= 1.675* 1106-27 kg)
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Unformatted text preview: Ans:; Okk, I know the formula is, lamda=h/mu Where m is mass, u is velocity , h= 6.63* 10^-34 Then I can find the wavelength. .but it says about thermal neutrons?? So at room temperature the situation will be different. .What should I do?? And it should b a beam of neutron. .while we have the mass of one neutron. I am confused. 6. How many Photons at 586 nm must be absorbed to melt 5.50*10^2 of ice? It takes 334 J to melt 1 g of ice? On average how many water molecules does one photon convert from ice to water? Ans:: I did the first one. But now sure about that. Its also, lamda=hc/E I guess. .not sure. .I just used the unit of h to get the number of photons. But not sure about it....
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