# This is driving me insane

#### TheoPetro

##### Banned
A certain crystalline solid can be probed using a wavelength of 0.070nm. What kinetic energy is required if the probe is
a. electrons

I dont want you to do this for me just a farken hint. I this it has something to do with

((h / .070nm)^2) / (2m) = K

h = plank's constant
m = mass of particle (in e- case its 9.1x10^-31 kg)
K = kinetic energy

I think thats how you do it but its just a guess. Im not sure how to relate K and lambda (wavelength). I dont usualy ask for homework help but this one has been kicking my ass for the past 2 hrs.

Thanks

#### Soccerman06

##### Diamond Member
If i wasnt drunk and it wasnt 3:30 in the morning, I might be able to help ya :laugh:

#### TheoPetro

##### Banned
Originally posted by: Soccerman06
If i wasnt drunk and it wasnt 3:30 in the morning, I might be able to help ya :laugh: but youre my only hope

#### cirthix

##### Diamond Member
"help me soccerman, you're my only hope" #### dxkj

##### Lifer
wavelength = h / momentum

momentum = mass * speed

kinetic energy = 1/2 mass * speed^2

so

wavelength = Plancks Constant / sqrt(2 * mass * kinetic energy)

to describe electrons volts for energy and nanometers for wavelength

wavelength = sqrt (1.5nm^2 *eV / Kinetic Energy)

as KE goes up, Lambda goes down.

and so on

#### Soccerman06

##### Diamond Member
Originally posted by: cirthix
"help me soccerman, you're my only hope" That is so going in my sig #### TheoPetro

##### Banned
Originally posted by: dxkj
wavelength = h / momentum

momentum = mass * speed

kinetic energy = 1/2 mass * speed^2

so

wavelength = Plancks Constant / sqrt(2 * mass * kinetic energy)

to describe electrons volts for energy and nanometers for wavelength

wavelength = sqrt (1.5nm^2 *eV / Kinetic Energy)

as KE goes up, Lambda goes down.

and so on
I understand that part. I think thats basically what I have. I just wasnt sure if that was the right way to go about this.

edit: unless im missing something completely obvious. It is 4am

#### dxkj

##### Lifer
Originally posted by: TheoPetro
Originally posted by: dxkj
wavelength = h / momentum

momentum = mass * speed

kinetic energy = 1/2 mass * speed^2

so

wavelength = Plancks Constant / sqrt(2 * mass * kinetic energy)

to describe electrons volts for energy and nanometers for wavelength

wavelength = sqrt (1.5nm^2 *eV / Kinetic Energy)

as KE goes up, Lambda goes down.

and so on
I understand that part. I think thats basically what I have. I just wasnt sure if that was the right way to go about this.
well you were asking how to relate wavelength and KE, and yes, this is the way to do it.

#### TheoPetro

##### Banned
Originally posted by: dxkj
Originally posted by: TheoPetro
Originally posted by: dxkj
wavelength = h / momentum

momentum = mass * speed

kinetic energy = 1/2 mass * speed^2

so

wavelength = Plancks Constant / sqrt(2 * mass * kinetic energy)

to describe electrons volts for energy and nanometers for wavelength

wavelength = sqrt (1.5nm^2 *eV / Kinetic Energy)

as KE goes up, Lambda goes down.

and so on
I understand that part. I think thats basically what I have. I just wasnt sure if that was the right way to go about this.
well you were asking how to relate wavelength and KE, and yes, this is the way to do it.
thanks

#### dxkj

##### Lifer
Originally posted by: TheoPetro
Originally posted by: dxkj
Originally posted by: TheoPetro
Originally posted by: dxkj
wavelength = h / momentum

momentum = mass * speed

kinetic energy = 1/2 mass * speed^2

so

wavelength = Plancks Constant / sqrt(2 * mass * kinetic energy)

to describe electrons volts for energy and nanometers for wavelength

wavelength = sqrt (1.5nm^2 *eV / Kinetic Energy)

as KE goes up, Lambda goes down.

and so on
I understand that part. I think thats basically what I have. I just wasnt sure if that was the right way to go about this.
well you were asking how to relate wavelength and KE, and yes, this is the way to do it.
thanks

No problem.

Disclaimer: I really know nothing about this #### TheoPetro

##### Banned
Originally posted by: dxkj
Originally posted by: TheoPetro
Originally posted by: dxkj
Originally posted by: TheoPetro
Originally posted by: dxkj
wavelength = h / momentum

momentum = mass * speed

kinetic energy = 1/2 mass * speed^2

so

wavelength = Plancks Constant / sqrt(2 * mass * kinetic energy)

to describe electrons volts for energy and nanometers for wavelength

wavelength = sqrt (1.5nm^2 *eV / Kinetic Energy)

as KE goes up, Lambda goes down.

and so on
I understand that part. I think thats basically what I have. I just wasnt sure if that was the right way to go about this.
well you were asking how to relate wavelength and KE, and yes, this is the way to do it.
thanks

No problem.

Disclaimer: I really know nothing about this  I really hope youre kidding. Owell its half a homework. I can deal with a 50% if its wrong I guess.

#### dxkj

##### Lifer
How did it work out?