## Question about speed of light rounding

$c=\lambda v$

isauramora3K
Posts: 20
Joined: Fri Sep 29, 2017 7:07 am

### Question about speed of light rounding

In problem 1.15 why did they round the speed of light (2.998 x 10^8) but in problem 1.17 they didn't (2.99792 x 10^8)?

sahiltelang-Discussion 1J
Posts: 50
Joined: Thu Jul 13, 2017 3:00 am

### Re: Question about speed of light rounding

Our TA remarked about this in our discussion section to use the constants provided by Professor Lavelle on his website (subsequently the same for the test).

Curtis Wong 2D
Posts: 62
Joined: Sat Jul 22, 2017 3:00 am

### Re: Question about speed of light rounding

I believe is that in problem 15, they had a number of 102.6, which has 4 significant figures so they round the speed of light to 4 sig figs. Meanwhile, in problem 17, they didn't specify a number so they used the actual number of the speed of light.

Clarissa Molina 1D
Posts: 55
Joined: Fri Sep 29, 2017 7:04 am

### Re: Question about speed of light rounding

Regarding the constant for the speed of light, should we always use 2.99792 x 10^8 or is it okay to round to 3.0 x 10^8? In the lectures 3.0x10^8 is used, but on the constants and equations sheet it says 2.99792 x 10^8

Jessica Benitez 1K
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

### Re: Question about speed of light rounding

I think using the value Dr. Lavelle provided on the constants and equations sheet will be the safest option then at the end round the result to the appropriate sig figs based on the problem.