An electron moving to the right at 3.0% the speed of light enters a uniform elec

ID: 1731908 • Letter: A

Question

An electron moving to the right at 3.0% the speed of light enters a uniform electric field parallel to its direction of motion.

Part A

Part complete

If the electron is to be brought to rest in the space of 3.0 cm , what direction is required for the electric field?

SubmitPrevious Answers

Correct

Part B ??????

What is the strength of the field?

Express your answer using two significant figures.

nothing

An electron moving to the right at 3.0% the speed of light enters a uniform electric field parallel to its direction of motion.

Part A

Part complete

If the electron is to be brought to rest in the space of 3.0 cm , what direction is required for the electric field?

to the left to the right

SubmitPrevious Answers

Correct

Part B ??????

What is the strength of the field?

Express your answer using two significant figures.

E =

nothing

N/C

Well, 3% of the speed of light is 9 million m/s, and is non-relativistic, so we can use the classical formula for KE;

1/2 m v^2 = 1/2 x 9.1E-31 x (9E6)^2 = 3.69E-17joules=eV, so divide 3.69E-17 by the charge on an electron 1.6E-19 to get

V= 230.6 volts. Divide this by 0.03 meters to get the strength of the field = 7700 N/C.

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