A) A 100-watt lightbulb radiates energy at a rate of 100 J/s. (The watt, a unit of power, or energy over time, is defined as 1 J
/s.) If all of the light emitted has a wavelength of 520 nm, how many photons are emitted per second? (Assume three significant figures in this calculation.)
Express your answer using three significant figures.
B) How much energy (in \({\rm J}\)) is contained in 1.00 mole of 490\({\rm nm}\) photons?
Express your answer to three significant figures and include the appropriate units.
C) What is the de Broglie wavelength of an electron traveling at 1.48
Express your answer using three significant figures.
B) How much energy (in \({\rm J}\)) is contained in 1.00 mole of 490\({\rm nm}\) photons?
Express your answer to three significant figures and include the appropriate units.
C) What is the de Broglie wavelength of an electron traveling at 1.48
1 answer:
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<u>Answer:</u> The half life of the sample of silver-112 is 3.303 hours.
<u>Explanation:</u>
All radioactive decay processes undergoes first order reaction.
To calculate the rate constant for first order reaction, we use the integrated rate law equation for first order, which is:
where,
k = rate constant = ?
t = time taken = 1.52 hrs
= Initial concentration of reactant = 100 g
[A] = Concentration of reactant left after time 't' = [100 - 27.3] = 72.7 g
Putting values in above equation, we get:
To calculate the half life period of first order reaction, we use the equation:
where,
= half life period of first order reaction = ?
k = rate constant =
Putting values in above equation, we get:
Hence, the half life of the sample of silver-112 is 3.303 hours.
Given is the specific heat of water equal to 4.18 Joule per gram per *C.
This means to raise the temperature of 1 g of water by 1 degree Celsius we need 4.18 joule of energy.
Now, look at the question. We are asked that how much amount of energy would be required to raise the temperature of 25 g of water by (54-50) = 4 degree celsius.
To do so we have formula
Q = m C (temperature difference)
Have a look at pic for answer
This means to raise the temperature of 1 g of water by 1 degree Celsius we need 4.18 joule of energy.
Now, look at the question. We are asked that how much amount of energy would be required to raise the temperature of 25 g of water by (54-50) = 4 degree celsius.
To do so we have formula
Q = m C (temperature difference)
Have a look at pic for answer