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Units

Posted: Tue Oct 22, 2019 2:59 pm
I'm having trouble with units when conducting some of these problems. Could anyone help me with the units of velocity, threshold energy, Plank's constant, and frequency?

Re: Units

Posted: Tue Oct 22, 2019 3:19 pm
Velocity: meters per second
Threshold energy: Joules
Plank's constant: Joules times seconds
Frequency: Hz (which is also cycles per second)

You can also find these on the constants and equations sheet that they give us during tests:
https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf

I hope this helps!

Re: Units

Posted: Tue Oct 22, 2019 3:32 pm
Reina Robles 1H wrote:Velocity: meters per second
Threshold energy: Joules
Plank's constant: Joules times seconds
Frequency: Hz (which is also cycles per second)

You can also find these on the constants and equations sheet that they give us during tests:
https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf

I hope this helps!

I completely agree with Reina's advice! Also, I highly recommend using the constants and equations sheet while solving homework problems to simulate a test situation. Additionally, I wanted to note that 1 Joule is equivalent to 1 kg⋅m2⋅s−2. This can help you cancel units, depending on what you're solving for. This conversion used to trip me up and it shows up a lot in the homework problems. I hope this helps!

-Rebecca

Re: Units

Posted: Tue Oct 22, 2019 9:06 pm
velocity: m/s
threshold energy: J or kg. m^2. s^-2
Planck's constant: 6.626 x 10^-34 Js or kg.m^2. s^-1
frequency: Hz or s^-1

Re: Units

Posted: Tue Oct 29, 2019 2:25 pm
Thank you everyone! I didn't realize we would be provided a list of constants. It would be a good idea for me to do the practice problems with this sheet to cancel out units.