## Constant for Speed of Light

$c=\lambda v$

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

### Constant for Speed of Light

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
Posts: 108
Joined: Sat Aug 24, 2019 12:15 am

### Re: Constant for Speed of Light

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

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

Justin Quan 4I
Posts: 104
Joined: Sat Sep 14, 2019 12:17 am

### Re: Constant for Speed of Light

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
Posts: 63
Joined: Fri Sep 27, 2019 12:30 am

### Re: Constant for Speed of Light

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

Ellis Song 4I
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Joined: Thu Jul 11, 2019 12:17 am

### Re: Constant for Speed of Light

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
Posts: 164
Joined: Fri Aug 30, 2019 12:16 am

### Re: Constant for Speed of Light

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
Posts: 107
Joined: Wed Sep 18, 2019 12:16 am

### Re: Constant for Speed of Light

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

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

Avnita C_4B
Posts: 50
Joined: Sat Sep 14, 2019 12:17 am

### Re: Constant for Speed of Light

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
Posts: 103
Joined: Wed Sep 18, 2019 12:21 am

### Re: Constant for Speed of Light

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
Posts: 79
Joined: Fri Aug 09, 2019 12:16 am

### Re: Constant for Speed of Light

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

Donna Nguyen 2L
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

### Re: Constant for Speed of Light

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
Posts: 54
Joined: Wed Sep 11, 2019 12:17 am

### Re: Constant for Speed of Light

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

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.