Speed of light


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

Speed of light

Postby Jessica Dharmawan 1G » Sun Nov 25, 2018 7:03 pm

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

Postby WilliamNguyen_4L » Sun Nov 25, 2018 7:07 pm

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

Postby sophiebillings1E » Sun Nov 25, 2018 7:11 pm

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

Michael Torres 4I
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Re: Speed of light

Postby Michael Torres 4I » Sun Nov 25, 2018 7:22 pm

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

Postby anthony_trieu2L » Sun Nov 25, 2018 7:42 pm

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

Postby clamond3F » Sun Nov 25, 2018 9:53 pm

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
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Re: Speed of light

Postby yuetao4k » Sun Nov 25, 2018 10:12 pm

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

Postby 604656370 » Sun Nov 25, 2018 10:23 pm

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

Postby Sheridan Slaterbeck 1J » Sun Nov 25, 2018 10:31 pm

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

Postby Jack Hewitt 2H » Thu Dec 06, 2018 6:29 pm

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

Postby Nina Do 4L » Thu Dec 06, 2018 9:16 pm

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

Postby Lopez_Melissa-Dis4E » Thu Dec 06, 2018 9:46 pm

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

Postby Lydia Luong 4L » Thu Dec 06, 2018 10:04 pm

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

Postby Mark 1D » Fri Dec 07, 2018 8:15 pm

3X10^8 should be fine I think


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