Planck's Constant


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Husnia Safi - 1K
Posts: 33
Joined: Fri Sep 29, 2017 7:04 am

Planck's Constant

Postby Husnia Safi - 1K » Sun Oct 15, 2017 8:50 pm

When would I need to use Planck's constant?

Andrea Grigsby 1I
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Joined: Fri Sep 29, 2017 7:03 am

Re: Planck's Constant

Postby Andrea Grigsby 1I » Sun Oct 15, 2017 9:00 pm

whenever you need to use an equation with the constant "h" in it.
eg E=hv

good thing is, the value is on the formula sheet so we don't have to memorize it :)

Ruohan Sun 3I
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Joined: Fri Sep 29, 2017 7:07 am

Re: Planck's Constant

Postby Ruohan Sun 3I » Sun Oct 15, 2017 9:11 pm

when using the equations E=hν and λ=h/p

Gurpreet Khamba 1J
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Joined: Fri Sep 29, 2017 7:04 am

Re: Planck's Constant

Postby Gurpreet Khamba 1J » Sun Oct 15, 2017 9:16 pm

It can also be used to find E (Energy) when the frequency is not known. To do this, you would use the relation v has with c (speed of light) and λ (wavelength).
This results in the equation: E = (hv)/λ
The constant is also used in the uncertainty principle.

Max Planck received a Nobel Prize in 1981 "in recognition of the services he rendered to the advancement of Physics by his discovery of energy quanta".

Michelle Lu 1F
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Been upvoted: 1 time

Re: Planck's Constant

Postby Michelle Lu 1F » Sun Oct 15, 2017 11:58 pm

Plank's constant is used in a variety of common equations such as E = (hv)/λ and λ=h/p and it was a constant that was found experimentally.

Susie Lee 2I
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Joined: Fri Sep 29, 2017 7:05 am

Re: Planck's Constant

Postby Susie Lee 2I » Mon Oct 16, 2017 11:12 pm

Whenever you see "h" in a formula! Don't get it confused with "p"!!

Adrian Lim 1G
Posts: 88
Joined: Fri Sep 29, 2017 7:03 am

Re: Planck's Constant

Postby Adrian Lim 1G » Tue Oct 17, 2017 2:45 pm

Planck's constant is a set number for the constant h. It is used in formulas, such as E = hv. It will be given to you on the formula sheet. Just to reiterate the above reply, don't get it confused with p. p stands for momentum and is equal to the mass * velocity.

Josh Moy 1H
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Joined: Thu Jul 13, 2017 3:00 am

Re: Planck's Constant

Postby Josh Moy 1H » Tue Oct 17, 2017 8:59 pm

Use planck's constant whenever you need to use/derive equations involving the variable h

Jasmin Tran 1J
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Joined: Thu Jul 27, 2017 3:00 am

Re: Planck's Constant

Postby Jasmin Tran 1J » Fri Oct 20, 2017 1:57 am

Also, make sure the variable is h and not "h bar" (the h with a cross on the top), because h bar refers to the uncertainty principle and has a different value than h, which is Planck's constant.

Patricia Macalalag 2E
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Re: Planck's Constant

Postby Patricia Macalalag 2E » Sat Oct 21, 2017 12:39 am

Don't forget that the units for Planck's Constant are joules times seconds!

Christy Zhao 1H
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

Re: Planck's Constant

Postby Christy Zhao 1H » Sun Oct 22, 2017 6:52 pm

You also use Planck's constant in the equation relating the kinetic energy of an ejected e- to the energy of an incident photon.


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