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**[SOLVED] physics 30 ...Matter..i would apresiate some help on this question ..**

**hi this is a cuestion from physics 30 grde 12 ...i need some help figuring out how to solve it ...the provlem is as folow..**

1. x-rays of wavelenght 5.0 x 10^-11m strike a free electron at rest. The free electron rebounds with a velocity of 2.0 x 10^6 m/s. The Scattered X-ray strikes a metallic surface whose work function is 5.2 x 10^-16J.

1. x-rays of wavelenght 5.0 x 10^-11m strike a free electron at rest. The free electron rebounds with a velocity of 2.0 x 10^6 m/s. The Scattered X-ray strikes a metallic surface whose work function is 5.2 x 10^-16J.

**What is the maximum velocity of an emitted photoelectron?**

a)2.0 x 10^6 m/s

b)8.7 x 10^7 m/s

c)4.3 x 10^4 m/s

d)5.4 x 10^5 m/s

a)2.0 x 10^6 m/s

b)8.7 x 10^7 m/s

c)4.3 x 10^4 m/s

d)5.4 x 10^5 m/s

**3. this is what i have done but im just confuse now ..im not sure if this is right:**

f'=w/h

=5.2 X 10^-16/6.63 x 10^-34

=(6.63 x 10^-34)(3.00 x 10^8)/5.0 x 10^-11m

=3.978 x 10^-15/6.63 x 10^-34

=(6.63 x 10^-34)(6 x 10^18) - (6.63 x 10^-34)( 7.85 x 10^17)

=3.46 x 10^-15J/1.60 x 10^-19c

there im stuck im not sure what else to do ..what formula was i supose to use..am i in the right way or not..? if there is someone that could help me solve this problem... it will be grate ..thanks..

**Ek=hf-hf'**f'=w/h

=5.2 X 10^-16/6.63 x 10^-34

__=7.85 x 10^17HZ__**E=hc/λ**=(6.63 x 10^-34)(3.00 x 10^8)/5.0 x 10^-11m

__=3.978 x 10^-15J__**f=E/h**=3.978 x 10^-15/6.63 x 10^-34

__=6 x 10^18HZ__**Ek=hf-hf'**=(6.63 x 10^-34)(6 x 10^18) - (6.63 x 10^-34)( 7.85 x 10^17)

__=3.46 x 10^-15J__**v=Ek/q**=3.46 x 10^-15J/1.60 x 10^-19c

__=2.2 X 10^4__there im stuck im not sure what else to do ..what formula was i supose to use..am i in the right way or not..? if there is someone that could help me solve this problem... it will be grate ..thanks..