Constant for Speed of Light


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Diana Chavez-Carrillo 2L
Posts: 122
Joined: Fri Sep 28, 2018 12:18 am

Constant for Speed of Light

Postby Diana Chavez-Carrillo 2L » Wed Oct 16, 2019 1:44 pm

I am wondering what constant would Lavelle prefer/require us to use throughout our homework problems and next exam when it comes to speed of light because the Solution Manual used 2.998*10^8 m*s^-1 but in my PLF we used 3.0*10^8 m*s^-1. I am aware that each one can you give you a different answer so I want to make sure I am using the correct constant for speed of light.

Jasmine Fendi 1D
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Joined: Sat Aug 24, 2019 12:15 am

Re: Constant for Speed of Light

Postby Jasmine Fendi 1D » Wed Oct 16, 2019 1:45 pm

I would use 2.998*10^8 m*s-1 because it would give you a more exact answer, but maybe ask your TA!

Alexa Hernandez 3k
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Re: Constant for Speed of Light

Postby Alexa Hernandez 3k » Wed Oct 16, 2019 1:48 pm

I think 2.998x10^8 is more accurate but definitely ask if your not positive.

Justin Quan 4I
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Re: Constant for Speed of Light

Postby Justin Quan 4I » Wed Oct 16, 2019 3:20 pm

Will there be a difference in our calculations if you used 3.0*10^8 verses 2.998*10^8? I would think using sig figs at the end of our answer our account for any difference in the answers.

PriscillaLi_3G
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Joined: Fri Sep 27, 2019 12:30 am

Re: Constant for Speed of Light

Postby PriscillaLi_3G » Wed Oct 16, 2019 3:26 pm

Lavelle generally uses 3.0 x 10^8 in class so I believe that is fine.

Ellis Song 4I
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Re: Constant for Speed of Light

Postby Ellis Song 4I » Wed Oct 16, 2019 3:51 pm

On Lavelle's website there is a link for a pdf with all the constants and equations and the speed of light used in that is 2.99792 × 10^8 m/s so I assume that using 2.998 would be fine

sarahsalama2E
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Re: Constant for Speed of Light

Postby sarahsalama2E » Wed Oct 16, 2019 4:59 pm

Personally, I have always used 3.0 x 10^8 m/s for the constant c and my answers have been correct, but I would just check the formula sheet that's given on the test next time just to be safe.

Jared Khoo 1G
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Joined: Wed Sep 18, 2019 12:16 am

Re: Constant for Speed of Light

Postby Jared Khoo 1G » Wed Oct 16, 2019 5:26 pm

Given he provides 2.99792 × 10^8 m/s on the formula sheet pdf, I would use that, although I'm sure he would specify/be fine with either on homework.

Arvind 4G
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Re: Constant for Speed of Light

Postby Arvind 4G » Thu Oct 17, 2019 1:29 am

I would use the more specific value as it will give you a more exact answer.

Avnita C_4B
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Re: Constant for Speed of Light

Postby Avnita C_4B » Thu Oct 17, 2019 2:18 am

It is best to use 2.99*10^8 as it is more accurate but make sure you ask your TA about it because when using it, you have to be careful about significant figures of the end result.

Anthony Hatashita 4H
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Joined: Wed Sep 18, 2019 12:21 am

Re: Constant for Speed of Light

Postby Anthony Hatashita 4H » Thu Oct 17, 2019 6:59 pm

2.998x10^8 is most accurate, but for some solutions in the manual it uses even more precise numbers. I think for the tests we're given the constants to use though so we should all be fine!

stephaniekim2K
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Joined: Fri Aug 09, 2019 12:16 am

Re: Constant for Speed of Light

Postby stephaniekim2K » Sun Oct 20, 2019 11:36 pm

For tests at least, I used the constant given on the front sheet and I got full points for the problem.

Donna Nguyen 2L
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Joined: Sat Aug 24, 2019 12:17 am

Re: Constant for Speed of Light

Postby Donna Nguyen 2L » Wed Oct 23, 2019 1:25 am

Both are correct. 2.998*10^8 m/s is more accurate, but I'm sure you can use 3.0*10^8 m/s as well, as it also gives an accurate answer.

Doreen Liu 4D
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Joined: Wed Sep 11, 2019 12:17 am

Re: Constant for Speed of Light

Postby Doreen Liu 4D » Wed Oct 23, 2019 11:09 am

In the solutions manual, often the value 2.99x10^8 is used, so I think for accuracy purposes, use the 2.99 value on the test.

Yiyang Jen Wang 4G
Posts: 76
Joined: Wed Nov 21, 2018 12:18 am

Re: Constant for Speed of Light

Postby Yiyang Jen Wang 4G » Mon Oct 28, 2019 9:00 pm

2.998*10^8 m/s is definitely more accurate, but 3.0*10^8 m/s is also not wrong for sure. If we can use a calculator then using the more accurate one is definitely more recommend.


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