## Speed of Light

thanh24mai
Posts: 50
Joined: Thu Jul 25, 2019 12:17 am

### Speed of Light

Is the speed of light always going to be 2.998 x 10^8 m/s? Is this a constant?

AKhanna_3H
Posts: 104
Joined: Wed Sep 18, 2019 12:19 am

### Re: Speed of Light

Yes it is a constant.

Pegah Nasseri 1K
Posts: 100
Joined: Wed Feb 27, 2019 12:15 am

### Re: Speed of Light

The speed of light will always be a constant and is labeled in equations as the variable "c". It is somewhere around 3.0 X 10^8 m/s. On exams, make sure to use the exact number for the speed of light that is given to you on the equation sheet of the exam. This will help you with getting the right number of sig figs and prevent any rounding errors.

Minh Ngo 4G
Posts: 137
Joined: Thu Jul 25, 2019 12:17 am

### Re: Speed of Light

Yes. It’s a constant. Some might write it like 3.00 x 10^8 since it’s easier to remember

Sharon Rodriguez 3H
Posts: 50
Joined: Wed Nov 14, 2018 12:18 am

### Re: Speed of Light

pegahnasseri_3L wrote:The speed of light will always be a constant and is labeled in equations as the variable "c". It is somewhere around 3.0 X 10^8 m/s. On exams, make sure to use the exact number for the speed of light that is given to you on the equation sheet of the exam. This will help you with getting the right number of sig figs and prevent any rounding errors.

So just making sure but using 2.998 x 10^8 would be for your own accuracy and wouldn't get any points knocked off on an exam if we used 3.0 instead, right?

Robert Tran 1B
Posts: 118
Joined: Thu Jul 11, 2019 12:15 am

### Re: Speed of Light

The speed of light will always be 3.0 * 10^8 m/s in a vacuum. This value is a constant; however, the speed of light can vary depending on the medium it is passing through.

Jamie Lee 1F
Posts: 106
Joined: Fri Aug 09, 2019 12:16 am

### Re: Speed of Light

Yes, speed of light (c) is a constant and will always be 2.998 x 10^8.

Jialun Chen 4F
Posts: 108
Joined: Sat Sep 07, 2019 12:16 am

### Re: Speed of Light

The speed of light is in fact a constant. I used to use 2.9979*10^8 more often but figured 2.998*10^8 is more commonly applied in this class.

Jingyao Chen 4H
Posts: 49
Joined: Fri Sep 27, 2019 12:19 am

### Re: Speed of Light

Yes. It is a constant and is universally agreed/defined as the length traveled by light in a vacuum condition in ​1⁄299792458 seconds.

Jamie Hwang 2F
Posts: 104
Joined: Thu Jul 25, 2019 12:16 am

### Re: Speed of Light

I always used 3.0*10^8 in high school but it's probably better to use the values from the constants and equations paper that is on Professor Lavelle's website.

Kyle Thorin
Posts: 50
Joined: Sat Aug 24, 2019 12:16 am

### Re: Speed of Light

The speed of light is a constant. It is 2.998 x 10^8 m/s

Kyle Thorin
Posts: 50
Joined: Sat Aug 24, 2019 12:16 am

### Re: Speed of Light

The speed of light is a constant. It is 2.998 x 10^8 m/s

Osvaldo SanchezF -1H
Posts: 122
Joined: Wed Sep 18, 2019 12:21 am

### Re: Speed of Light

Sharon Rodriguez 3H wrote:
pegahnasseri_3L wrote:The speed of light will always be a constant and is labeled in equations as the variable "c". It is somewhere around 3.0 X 10^8 m/s. On exams, make sure to use the exact number for the speed of light that is given to you on the equation sheet of the exam. This will help you with getting the right number of sig figs and prevent any rounding errors.

So just making sure but using 2.998 x 10^8 would be for your own accuracy and wouldn't get any points knocked off on an exam if we used 3.0 instead, right?

It all depends how technical your TA is with rounding as some TA's pay more attention to it than others. So to be sure just use that 2.88 x 10^8 so that you don't risk losing any points.

Ashley Kumar 3F
Posts: 50
Joined: Sat Sep 07, 2019 12:18 am

### Re: Speed of Light

Always the same number!

Anvi Brahmbhatt 4A
Posts: 51
Joined: Wed Sep 18, 2019 12:21 am

### Re: Speed of Light

The speed of light is a constant. I would use the value given on the equation sheet just to be safe.

405404782 Gabriel Rigole 4F
Posts: 56
Joined: Sat Aug 17, 2019 12:18 am

### Re: Speed of Light

yes because the speed of light is a consent, C.

Tyler Angtuaco 1G
Posts: 130
Joined: Wed Sep 11, 2019 12:16 am

### Re: Speed of Light

Yes that is the speed of light and it is a constant. But, for simplicity, it is also acceptable to use 3.0x10^8 m/s. This is one of the key concepts of the photoelectric effect and is necessary for understanding the correlation between light, its frequency, its wavelength, and its energy. Also keep in mind that it is the speed of light, so the constant may be used for velocity in some scenarios.

MTanikella_1K
Posts: 110
Joined: Sat Jul 20, 2019 12:16 am

### Re: Speed of Light

Yes the speed of light is a constant and you can use 2.998*10^8 or 3.0*10^8 for its value.

nshahwan 1L
Posts: 100
Joined: Fri Aug 30, 2019 12:18 am

### Re: Speed of Light

is it better to use 2.998 or 3?

Betania Hernandez 2E
Posts: 107
Joined: Fri Aug 02, 2019 12:15 am

### Re: Speed of Light

The speed of light is always a constant. It would be better to use the exact number provided on the equation sheet (2.99792*10^8) on the exams.

Anna Chen 1K
Posts: 104
Joined: Thu Jul 25, 2019 12:18 am

### Re: Speed of Light

Yes, the speed of light is always going to be 2.998 x 10^8 m/s. It is always going to be a constant too. Sometimes, it is rounded to 3.00 x 10^8 m/s; however, using 2.998 x 10^8 m/s is recommended for accuracy.

Kimme Chun 1I
Posts: 22
Joined: Sat Sep 07, 2019 12:17 am
Been upvoted: 1 time

### Re: Speed of Light

The speed of light is a constant and is represented by the letter "c". It is approximately 3.0*10^8 m/s.

Areli C 1L
Posts: 95
Joined: Wed Nov 14, 2018 12:19 am

### Re: Speed of Light

Yes, it is a constant. Some prefer to write it as 3.00x10^8 or 2.998x10^8 believe it or not sometimes, depending on which one you use, it can change your answer slightly. So for accuracy try to use the 2.998x10^8. Then your final answer should be in the appropriate Sig figs :)

Robert Cross 1A
Posts: 35
Joined: Wed Sep 11, 2019 12:15 am

### Re: Speed of Light

For the purposes of this class I think we're best off using the value given to us on Lavelle's equation sheet

jvera4b
Posts: 60
Joined: Wed Sep 11, 2019 12:17 am

### Re: Speed of Light

The speed of light is a constant (2.998 x 10^8) as others have mentioned 3.0 x 10^8 is sometimes used, however it would be better if you used 2.998 x 10^8 so that your sig figs at the end are correct.

Lelija Kazlauskas 3J
Posts: 50
Joined: Thu Jul 11, 2019 12:16 am

### Re: Speed of Light

The speed of light is a constant, as seen through experimental data. For which version of the speed of light to use, my TA said to usually use 3.00*10^8 m/s, unless the constant/equation sheet or problem you are given says another number instead.

Emil Velasco 1H
Posts: 96
Joined: Wed Nov 21, 2018 12:19 am

### Re: Speed of Light

The speed of light is constant at 2.998x10^8 m.s^-1

Aarushi Solanki 4F
Posts: 107
Joined: Sat Jul 20, 2019 12:17 am

### Re: Speed of Light

Yes, the speed of light (2.998*10^8 m/s) is always a constant, as long as this light is traveling in a vacuum-like medium.

Vivianvelazquez_1J
Posts: 109
Joined: Thu Jul 11, 2019 12:17 am
Been upvoted: 1 time

### Re: Speed of Light

Natalia Shahwan 4H wrote:is it better to use 2.998 or 3?
I think it's better to use 3 x 10^8 instead of 2.998 x 10^8 simply because it's a whole and easier to remember. Most of the times the solutions usually use 3 x 10^8.

Abraham De Luna
Posts: 31
Joined: Sat Sep 14, 2019 12:16 am

### Re: Speed of Light

Yes, it is a constant so it will always be the same.