## Ch.1 #41 [ENDORSED]

Jocelyn Martinez-1K
Posts: 4
Joined: Tue Nov 15, 2016 3:00 am

### Ch.1 #41

We are asked to "find the velocity of a neutron of wavelength 100. pm" so we set the equation to v=h/mλ. So h=6.62608x10^-34, λ= 100 (given), and m=1.67493x10^-27 kg. My question is where did we get 'm' from? Is m a constant? Looking for clarification of where we get m=1.67493x10^-27 kg.

Gwen Peng 1L
Posts: 36
Joined: Sat Jul 22, 2017 3:01 am

### Re: Ch.1 #41  [ENDORSED]

So yes the mass of a neutron is always constant. The mass of a neutron is 1 amu. Therefore you convert this to kilograms and get:
1 amu = 1.67493x10^-27 kg

Lily Sperling 1E
Posts: 49
Joined: Tue Oct 10, 2017 7:14 am

### Re: Ch.1 #41

Yes, Gwen is correct. The mass of a neutron, like that of a proton, or planks constant, or Avogadro's number are all constant and therefore, will not change. The mass of a neutron is typically given in grams, so you have to convert by dividing by 1000 in order to get kg.

Posts: 41
Joined: Wed Nov 15, 2017 3:01 am

### Re: Ch.1 #41

You have to convert the picometers into meters before plugging it into the equation right?

ErinKim1I
Posts: 31
Joined: Fri Apr 06, 2018 11:03 am

### Re: Ch.1 #41

Yes, you have to convert picometers to meters because m is the standard SI unit

Emely Reyna 1F
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

### Re: Ch.1 #41

to convert from pm to m in order to use the equation you can multiply 100 pm by 10^-12

Aman Sankineni 2L
Posts: 103
Joined: Fri Aug 30, 2019 12:17 am