An electron \((q=-e)\) completes half of a circular orbit of radius \(r\) around a nucleus with \(Q=+3 e\), as shown in Figure Q21.4.

a. How much work is done on the electron as it moves from \(\mathrm{i}\) to \(\mathrm{f}\) ? Give either a numerical value or an expression from which you could calculate the value if you knew the radius. Justify your answer.

b. By how much does the electric potential energy change as the electron moves from i to f?

c. Is the electron's speed at f greater than, less than, or equal to its speed at i?

d. Are your answers to parts a and c consistent with each other?

Transcribed Image Text:

FIGURE Q21.4