An electron with an initial speed of 420,000 m/s is brought to rest by an electr

Question

An electron with an initial speed of 420,000 m/s is brought to rest by an electric field.

Did the electron move into a region of higher potential or lower potential?

Part 1)

D.) Because the electron is a positive charge and it accelerates as it travels, it must be moving from a region of lower potential to a region of higher potential.

Part 2)

What was the potential difference that stopped the electron?

Express your answer to two significant figures and include the appropriate units (V).

A.) Because the electron is a negative charge and it slows down as it travels, it must be moving from a region of higher potential to a region of lower potential. B.) Because the electron is a positive charge and it accelerates as it travels, it must be moving from a region of higher potential to a region of lower potential. C.) Because the electron is a negative charge and it slows down as it travels, it must be moving from a region of lower potential to a region of higher potential.

D.) Because the electron is a positive charge and it accelerates as it travels, it must be moving from a region of lower potential to a region of higher potential.

Part 2)

What was the potential difference that stopped the electron?

Express your answer to two significant figures and include the appropriate units (V).

Explanation / Answer

A.) Because the electron is a negative charge and it slows down as it travels, it must be moving from a region of higher potential to a region of lower potential.

Because, from conservation of Energy

1/2 m v^2 = q V

intially V is higher enough to accelerate electron to the given speed, but then later it enetrs such a region where potential is very low and eventually it stops.

B)q (V2 ) = 1/2 m (v2^2 - v1^2)

V2 - V1 = 0.5 x 9.1 x 10^-31 [ 0 - (4.2 x 10^5)^2 ] / (1.6 x 10^-19) = -0.501 V

Hence, V = 0.501 V

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.