Express all your answer using two significant figures. A.Calculate the voltage r

Question

Express all your answer using two significant figures.

A.Calculate the voltage required to accelerate a beam of electrons initially at rest if they have a kinetic energy of 3.5 eV .

B.Calculate their speed if they have a kinetic energy of 3.5 eV .

c.Calculate the voltage required to accelerate a beam of electrons initially at rest if they have a kinetic energy of 4.7 keV .

D.Calculate their speed if they have a kinetic energy of 4.7 keV .

F.Calculate their speed if they have a kinetic energy of 7.0×1016 J .ECalculate the voltage required to accelerate a beam of electrons initially at rest if they have a kinetic energy of 7.0×1016 J .

Explanation / Answer

A)
KE = Q*V
3.5eV = e*V
V=25 V
Since Q = e (charge of an electron)
Answer: 25 V

B)
K.E = 3.5 eV = 3.5*1.6*10^-19 J = 5.6*10^-19 J
use:
K.E = 0.5*m*v^2
5.6*10^-19 = 0.5* (9.1*10^-31) * v^2
v = 1.11*10^6 m/s
Answer: 1.11*10^6 m/s

C)
KE = Q*V
4.7 KeV = e*V
V=4.7 KV
Answer: 4.7 KV

D)
K.E = 4.7 KeV = 4.7*10^3 eV = 4.7*10^3*1.6*10^-19 J = 7.52*10^-16 J
use:
K.E = 0.5*m*v^2
7.52*10^-16 = 0.5* (9.1*10^-31) * v^2
v = 4.07*10^7 m/s
Answer: 4.07*10^7 m/s

I am allowed to answer only 4 parts at a time

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