Module Question #17

[Alysia Garcia 1B]

For this question, I am just multiplying the speed of light by 1/100 by the mass of the electron (9.109x10^-31 kg) to find the uncertainty in momentum. This gave me 3x10^6 and then divided h/4pi by the number I found but I somehow am not getting any of the given answers. Does anyone know what error I am making?

[Nahelly Alfaro-2C]

You are starting the problem correctly by multiplying the speed of light to the mass of an electron to 1/100; however, your uncertainty in momentum is not 3x10^6. The uncertainty in momentum is actually 2.731 x 10^-24 which is the mistake is made. From there like you mentioned, you would divide the uncertainty in momentum by h/4pi which will give the answer to one of the answer choices provided in the question.

[abbydouglas1K]

Why do the answers have 1 sig fig ?

[zoepamonag4C]

I think it's because 3.0x10^6 has 1 sig fig.

[Gillian Ward 1F]

I thought of it as 1/100 having one sig fig