## Speed of Light constant

$c=\lambda v$

Alexis Webb 2B
Posts: 124
Joined: Thu Jul 11, 2019 12:15 am

### Speed of Light constant

Is it okay to use 3.00x 10^8 m/s instead of 2.99792x10^8m/s for the constant c? It typically comes out with the same answer just rounded more.

MingdaH 3B
Posts: 133
Joined: Thu Jul 11, 2019 12:17 am

### Re: Speed of Light constant

Unless all of the other values in a question also have like 6 sigfigs, like 2.99792x10^8m/s, there's no reason to be that precise, since the final answer will round off the extra digits anyways.

Jack Riley 4f
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

### Re: Speed of Light constant

When he introduced the speed of light in class he used 3.00x10^8 m/s so I think that's what we should use.

Ryan Chang 1C
Posts: 105
Joined: Sat Aug 24, 2019 12:17 am

### Re: Speed of Light constant

I've been using 3.00x10^8 m/s for module and homework problems and have been just fine.

Abby Soriano 1J
Posts: 103
Joined: Sat Aug 24, 2019 12:16 am

### Re: Speed of Light constant

If you really wanted to use a constant that's a little more precise than 3.00x10^8 m/s but less tedious than 2.99792x10^8 m/s, I'd suggest using 2.998x10^8 m/s. But then again it shouldn't matter too much as long as your final sig figs are correct.

KaleenaJezycki_1I
Posts: 127
Joined: Sat Aug 17, 2019 12:18 am
Been upvoted: 2 times

### Re: Speed of Light constant

I think ideally it would be easier to use 3.00x10^8 m/s for the speed of light because 1. that is what Lavelle uses and 2. because it's slightly easier to remember as well as write down when you are working at a faster pace to complete a test or so on. It should not throw off your sig figs and I'm not entirely sure but I think there should be some sort of leniency on sig figs as in there is a range of maybe .02 above or below the answer that you can be off on.

Michelle Xie 2B
Posts: 99
Joined: Sat Aug 17, 2019 12:18 am

### Re: Speed of Light constant

I usually just use 3.00 unless theres like another value with a crazy amount of sig figs. It should be fine since Prof. Lavelle also used it.

105335337
Posts: 103
Joined: Sat Aug 24, 2019 12:15 am

### Re: Speed of Light constant

3.00 x 10^8 is acceptable to use in almost all cases since we do not need the specificity that the actual number implies. In a case where any said number could change the result and have a large effect, then you would use the 2.9 value, but we do not have that in this class.