Maple TA 27-2

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Maple TA 27-2

Post  DJ on Sun May 03, 2009 1:18 pm

Explanations here.

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27-2 #1

Post  DJ on Sun May 03, 2009 1:20 pm

Use the equation: DeltaE = (m-M)*c^2

The difference between the two masses is given already. Now, if you integrate the MeV conversion into the equation as shown on sheet 17, we get:

DeltaE = (m-M)*931.5

Plug in the number between the parenthesis and solve. That is the answer.

Answer is negative.

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27-2 #2

Post  DJ on Sun May 03, 2009 1:43 pm

Use the same equation (with MeV factor integrated): DeltaE = (m-M)*931.5

Now, different numbers of particles are given. Since it is a neutral atom, we assume that the mass of a hydrogen atom can be used for the electrons and protons. However, we will need to add in the mass of the neutrons. So:

(# of protons * 1.007825) + (# of neutrons * 1.008665) = m

Now, plug it into the equation DeltaE = (m-M)*931.5. We just calculated m, and M is given in the question.

This answer, DeltaE, needs to be divided by M because we are trying to find the E per nucleon. That is the answer.

Answer is positive.

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27-2 #3

Post  DJ on Sun May 03, 2009 1:49 pm

The number of protons will remain the same.

Answer is positive.


Last edited by DJ on Sun May 03, 2009 4:51 pm; edited 1 time in total

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#4

Post  phyfrk on Sun May 03, 2009 2:22 pm

any luck on question 4
i've tried a few different things but still having no luck

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Re: Maple TA 27-2

Post  DJ on Sun May 03, 2009 2:25 pm

phyfrk wrote:any luck on question 4
i've tried a few different things but still having no luck

Same here. Neutral

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number three

Post  yo on Sun May 03, 2009 4:41 pm

Actually proton number changes it is Z+1 for the answer. positive.

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Re: Maple TA 27-2

Post  DJ on Sun May 03, 2009 4:51 pm

yo wrote:Actually proton number changes it is Z+1 for the answer. positive.

My posted solution worked for me.

There may be two variations of the question.

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question 4

Post  sjames on Sun May 03, 2009 5:22 pm

Any ideas on number four I am having trouble with it as well.

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Re:Quest 3

Post  ... on Mon May 04, 2009 11:14 am

Maple TA accepted answers from 131 to 135 for me when my number given was 132.. So Z and Z+1 give you the correct answer according to Maple TA.

...
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27-4

Post  Yummy on Tue May 05, 2009 12:22 am

4. Take the mass given and * 931.5 to get KE in Mev then subtract 0.51MeV to correct for the electron.

Ans. neg

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Q#2

Post  phent on Tue May 05, 2009 2:58 pm

i have trying to follow the equation given above but i keep getting the wrong answer for #2. any help? i get answer like 8.5623

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Re: Maple TA 27-2

Post  DJ on Tue May 05, 2009 5:04 pm

phent wrote:i have trying to follow the equation given above but i keep getting the wrong answer for #2. any help? i get answer like 8.5623

What are your given values?

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please help me with my ques

Post  bo on Tue May 05, 2009 6:04 pm

the method i tried on top doesnt work!!

You "throw together" 30 protons, 35 neutrons and 30 electrons forming a hypothetical atom with an atomic mass of 64.954432 u. What is the binding energy per nucleon in MeV (sheet 13,16) ? Indicate with a positive (negative) sign whether energy is released by (input into) the formation of the atom. (Atomic masses in u: proton 1.007276,neutron 1.008665,electron 0.000549 and neutral H atom 1.007825. Note that the atomic masses (like 64.954432 ) are quoted for the neutral atom. Calculate with the quoted accuracy and enter your answer with the usual 4 significant digits).

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Q#2

Post  Phent on Tue May 05, 2009 10:55 pm

DJ.. these are the values.. thanks

You "throw together" 30 protons, 35 neutrons and 30 electrons forming a hypothetical atom with an atomic mass of 64.924767 u. What is the binding energy per nucleon in MeV (sheet 13,16) ? Indicate with a positive (negative) sign whether energy is released by (input into) the formation of the atom. (Atomic masses in u: proton 1.007276,neutron 1.008665,electron 0.000549 and neutral H atom 1.007825. Note that the atomic masses (like 64.924767 ) are quoted for the neutral atom. Calculate with the quoted accuracy and enter your answer with the usual 4 significant digits).

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Q#2

Post  El on Tue May 05, 2009 11:17 pm

The question asks how much energy is lost per nucleon. Nucleon=proton+neutron.

energy = mass so you must find out how much mass is lost.

Add up all the masses of the proton, neutron, and electron. Subtract that from the actual mass (what is given). That is the mass lost to energy. This is in atomic mass units. You must convert to kg.

1 atomic mass unit = 1.66053886 × 10-27 kilograms

e=mc^2 <----- very important

note that this will be in joules. you need to convert this into Mev/nucleon. So you must convert to Mev and divide by number of nucleons.

1 MeV = 1.6x10-13 J

As mass is lost - energy is released so you should know the sign of the answer.

Need a tutor? email el@tantalizingstitches.com

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Question 2 for PHENT

Post  Guest786 on Tue May 05, 2009 11:38 pm

This your question right?

You "throw together" 30 protons, 35 neutrons and 30 electrons forming a hypothetical atom with an atomic mass of 64.924767 u. What is the binding energy per nucleon in MeV (sheet 13,16) ? Indicate with a positive (negative) sign whether energy is released by (input into) the formation of the atom. (Atomic masses in u: proton 1.007276,neutron 1.008665,electron 0.000549 and neutral H atom 1.007825. Note that the atomic masses (like 64.924767 ) are quoted for the neutral atom. Calculate with the quoted accuracy and enter your answer with the usual 4 significant digits).


First you do this:

(30*1.007825) + (35*1.008665)= 65.538025

Then:

(65.538025-64.924767)*931.5/64.924767 = 8.7986

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Re: Maple TA 27-2

Post  :) on Wed May 06, 2009 3:38 am

thank you all~ number 2 was what i needed help with! Very Happy

:)
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Question 1

Post  to DJ on Wed May 06, 2009 10:12 am

can you show your work for the 931.5 MeV conversion factor?

to DJ
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Re: Maple TA 27-2

Post  TI83 on Thu May 14, 2009 3:05 pm

can you show your work for the 931.5 MeV conversion factor?

Delta E = mass difference * c^2

if the mass difference is 1u (1.66E-27) you get

Delta E = 1.66E-27*(3E8)^2 = 1.494E-10 J

1.494E-10J/(1.6E-19 J per eV) = 933750000 eV

933750000/ 10E6 = 933.75 MeV

These are the calculations...for some reason I am getting 933.75 instead of the 931.5 quoted in the notes...

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Re: Maple TA 27-2

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