units


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sarahartzell1A
Posts: 56
Joined: Fri Sep 28, 2018 12:17 am

units

Postby sarahartzell1A » Thu Oct 18, 2018 5:56 pm

When using DeBroglie's equation do you have to calculate given values into certain units before putting them into the equation?

Douglas Nguyen 2J
Posts: 71
Joined: Fri Sep 28, 2018 12:15 am

Re: units

Postby Douglas Nguyen 2J » Thu Oct 18, 2018 6:14 pm

When using DeBroglie's equation do you have to calculate given values into certain units before putting them into the equation?


DeBroglie's wavelength formula is lambda=h/mv. Lambda (wavelength) must be in meters but can be converted after the calculation if the question asks for a different unit.Planck's constant is given in J*s, momentum is given in kg*m/s, mass is given in kg, and velocity is given in m/s. If not converted to the proper units, the units won't cancel each other out.

Chloe Thorpe 1J
Posts: 77
Joined: Fri Sep 28, 2018 12:16 am

Re: units

Postby Chloe Thorpe 1J » Thu Oct 18, 2018 8:18 pm

Yes, you have to convert the units to SI units in order to cross out the units. It helps if you write out all the units, like 1 J = 1 kg*m^2*s^-2, and then cross off as you go to make sure you get the right conversion.

Hanniel U 2B
Posts: 76
Joined: Fri Sep 28, 2018 12:16 am

Re: units

Postby Hanniel U 2B » Thu Oct 18, 2018 8:21 pm

It depends. Sometimes you would have to use kg*m^2*s^-2 instead of J*s to cancel out and get the right units at the end of your calculations.


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