## units

$\lambda=\frac{h}{p}$

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

### units

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

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

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

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.