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Speed of light

Posted: Sun Nov 25, 2018 7:03 pm
by Jessica Dharmawan 1G
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?

Re: Speed of light

Posted: Sun Nov 25, 2018 7:07 pm
by WilliamNguyen_4L
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.

Re: Speed of light

Posted: Sun Nov 25, 2018 7:11 pm
by sophiebillings1E
It depends on the sig fig in the problem stay true to that.

Re: Speed of light

Posted: Sun Nov 25, 2018 7:22 pm
by Michael Torres 4I
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.

Re: Speed of light

Posted: Sun Nov 25, 2018 7:42 pm
by anthony_trieu2L
Just to be safe, you should use the constant given on the formula sheet. Otherwise, ask your TA for their preference.

Re: Speed of light

Posted: Sun Nov 25, 2018 9:53 pm
by clamond3F
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.

Re: Speed of light

Posted: Sun Nov 25, 2018 10:12 pm
by yuetao4k
Use the given constants until the end of the problem and then round to your significant figures!

Re: Speed of light

Posted: Sun Nov 25, 2018 10:23 pm
by 604656370
I've been using 3.0X10^8 m/s but just to be safe, use the constants he provides on the formula sheet.

Re: Speed of light

Posted: Sun Nov 25, 2018 10:31 pm
by Sheridan Slaterbeck 1J
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.

Re: Speed of light

Posted: Thu Dec 06, 2018 6:29 pm
by Jack Hewitt 2H
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.

Re: Speed of light

Posted: Thu Dec 06, 2018 9:16 pm
by Nina Do 4L
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.

Re: Speed of light

Posted: Thu Dec 06, 2018 9:46 pm
by Lopez_Melissa-Dis4E
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.

Re: Speed of light

Posted: Thu Dec 06, 2018 10:04 pm
by Lydia Luong 4L
I haven't had any issues with using 3.0 x 10^8, I think you should be able to use this!

Re: Speed of light

Posted: Fri Dec 07, 2018 8:15 pm
by Mark 1D
3X10^8 should be fine I think