## Speed of light

$c=\lambda v$

Jessica Dharmawan 1G
Posts: 32
Joined: Fri Sep 28, 2018 12:15 am

### Speed of light

When doing calculations, should we use 2.99792 × 108 m.s-1 or 3.00 × 108 m.s-1 for the speed of light?
I used the 3.00 × 108 m.s-1 on the midterm and got an answer that was two hundredths off and got it marked wrong, so what should be the accurate number to use?

WilliamNguyen_4L
Posts: 65
Joined: Fri Sep 28, 2018 12:28 am

### Re: Speed of light

I've been using the speed of light as 3.0 x 10^8 and I've had no problems with getting the correct answers on the tests and midterms.

sophiebillings1E
Posts: 60
Joined: Fri Sep 28, 2018 12:27 am

### Re: Speed of light

It depends on the sig fig in the problem stay true to that.

Michael Torres 4I
Posts: 92
Joined: Thu May 10, 2018 3:00 am
Been upvoted: 1 time

### Re: Speed of light

I have had no issue using 3.0*10^8 m/s on my exams. I recommend asking your TA about the problem you missed to see what they recommend.

anthony_trieu2L
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

### Re: Speed of light

Just to be safe, you should use the constant given on the formula sheet. Otherwise, ask your TA for their preference.

clamond3F
Posts: 8
Joined: Fri Sep 28, 2018 12:23 am

### Re: Speed of light

For homework, I have just been using 3.0x10^8 m/s and it is fine, but for the tests my TA said that the answers on their score sheet are calculated using the exact constants that are on the equation sheet.

yuetao4k
Posts: 60
Joined: Fri Sep 28, 2018 12:27 am
Been upvoted: 1 time

### Re: Speed of light

Use the given constants until the end of the problem and then round to your significant figures!

604656370
Posts: 30
Joined: Fri Sep 28, 2018 12:25 am

### Re: Speed of light

I've been using 3.0X10^8 m/s but just to be safe, use the constants he provides on the formula sheet.

Sheridan Slaterbeck 1J
Posts: 62
Joined: Fri Sep 28, 2018 12:27 am

### Re: Speed of light

My TA said to use the number given on the equation sheet otherwise rounding may affect your final answer and they can take points off for that.

Jack Hewitt 2H
Posts: 67
Joined: Fri Sep 28, 2018 12:27 am

### Re: Speed of light

Jessica Dharmawan 1G wrote:When doing calculations, should we use 2.99792 × 108 m.s-1 or 3.00 × 108 m.s-1 for the speed of light?
I used the 3.00 × 108 m.s-1 on the midterm and got an answer that was two hundredths off and got it marked wrong, so what should be the accurate number to use?

Look at the sig figs in the problem and use that as a guideline.

Nina Do 4L
Posts: 61
Joined: Fri Sep 28, 2018 12:27 am

### Re: Speed of light

In the past I have used 3.0 x 10 ^ 8m/s and never saw any problems. However, a coversheet with some equations will be given to us so I'd use that if you're unsure.

Lopez_Melissa-Dis4E
Posts: 66
Joined: Fri Sep 28, 2018 12:20 am

### Re: Speed of light

Personally, I would just use the constant given on the formula sheet to be safe. However you should be aware of significant figures to ensure the correct answer.

Lydia Luong 4L
Posts: 59
Joined: Fri Sep 28, 2018 12:24 am

### Re: Speed of light

I haven't had any issues with using 3.0 x 10^8, I think you should be able to use this!

Mark 1D
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

### Re: Speed of light

3X10^8 should be fine I think