- #1
LionLieOn
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Homework Statement
So me and my friend were comparing our homework and we noticed that although we had the same answers, we both had different ways of answer them.
So I was just wondering who's work, my friend or mine, is the most correct?Here's the questions.
1. Calculate the momentum of a 140 eV photon.
2. A certain microscopic object has a wavelength of 8.4 X 10-14 m and a speed of 1.2 X 105 m/s. What is the mass of the object?
Homework Equations
The Attempt at a Solution
Answers for the first question.My work:
140 eV Convert into joules:
E=(1.60 X 10-19)(140)
E= 2.24 X 10-17 J
Finding momentum:
p=E/c
p=(2.24 X 10-17) / ( 3.0 X 108 )
p= 7.466666667 X 10-26
Rounded,
p= 7.5 X 10-26 kgm/s
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My friends work:140 eV Convert into joules:
E=(1.60 X 10-19)(140)
E= 2.24 X 10-17 J
First find the wavelength:
E=hc/ (Lambda symbol)
(Lambda symbol)= hc/E
(Lambda symbol)= 8.9 X 10-9 m
Now find momentum:
p=h/ (Lambda symbol)
p=(6.63 X 10-34) / (8.9 X 10-9 )
p= 7.5 X 10 -26 kgm/s
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Second question.
My work:
(Lambda symbol) = h/mv
m=h/ (Lambda symbol)v
m= (6.63 X 10-34)/ (8.4 X 10-14) (1.2 X 105)
m= 6.577380952 X 10-26)
Rounded,
m= 6.6 X 10-26) kg
---------------------------------------------------------
my friends work:
Finding momentum of the object.
p= h/ (Lambda Symbol)
p= (6.63 X 10-34) / (8.4 X 10-14)
p= 7.89 X 10-21 kgm/s
Now find the mass of the object
p=mv
m=p/v
m= 7.89 X 10-21 / (1.2 X 105)
m= 6.577 X 10-26
Rounded,
m= 6.6 X 10-26 kg