How Fast Must an Electron Travel to Excite a Hydrogen Atom?

[ke0nGz]

i have problem solving this.. help please?

The 1st excitation energy of hydrogen atom is 10.2eV
calc the speed of the slowest electron that can excite a hydrogen atom..

(electron charge/mass ratio e/m = 1.7 x 10^11 C kg^-1)

C(speed of light ) is 3 x 10^8 ms^-1
h(planks constant) is 6.6 x 10 ^ ^-34 Js

thats all the given information

the answer is 1.9 x 10⁶ms^-1

 

[Redbelly98]

The kinetic energy of the electron gets transferred to the excitation energy of the hydrogen atom.

Can you express that statement in an equation?

p.s. Welcome to PF.

 

[ke0nGz]

er..

hf = work function energy?

1st excitation energy is work function energy?
speed of the slowest electron is the hf oso = 1/2 mv^2?

 

[Redbelly98]

The kinetic energy of the electron gets transferred to the excitation energy of the hydrogen atom.

speed of the slowest electron is the hf oso = 1/2 mv^2?

You're half-way correct, since 1/2 m v^2 is the kinetic energy of the electron.

What is the excitation energy of the atom?