An electron with an initial speed of 300,000 m/s is brought to rest by an electr

Question

An electron with an initial speed of 300,000 m/s is brought to rest by an electric field. 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.

a) What was the potential difference that stopped the electron?

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

b)What was the initial kinetic energy of the electron, in electron volts?

Express your answer using two significant figures.

Explanation / Answer

a) Apply, Workdone on electron = change in kinetic energy

q*dV = kf - Ki

q*dV = -0.5*m*v^2 (since kf = 0)

==> dV = -0.5*m*v^2/q

= 0.5*9.1*10^-31*(300000)^2/(-1.6*10^-19)

= 0.26 volts

b) Ki = q*dV

= e*0.26

= 0.26 eV

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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