Problem 14(6.25 points) A He ion is moving towards a proton (p) as shown in the
ID: 2036524 • Letter: P
Question
Problem 14(6.25 points) A He ion is moving towards a proton (p) as shown in the figure. The position of the proton is fixed. The dashed circles represent the equipotential surfaces around the proton and the electric potentials for each surface are shown in the figure. Initially, the He2+ion is so far away from the proton so that the electric potential at that point is essentially equal to zero. The initial kinetic energy of the Hea* ion is 20 eV. Which of the following correctly describes the motion of the Hea* ion: (Note: charge for He2+ ion = +3.2x10-19 C; charge of proton = +1.6x1019 C; i eV-1.6 x?049J) 10 V 20 V : A Hež* A) It will stop at point A and it will be bounced back B) It will stop at point B and it will be bounced back C) It will stop at point C and it will be bounced baclk D) It will not stop until it touches the proton E) Insufficient information to determine at which point the He ion will stop.Explanation / Answer
initial PE = 0
KE = 20 eV
when it stops then KE = 0
Applying energy conservation,
PEi + KEi = PEf + EKf
0 + 20 = q V + 0
20 = (2e) V
V = 10 Volt
Ans: (A) it will stop at point A and it will bounce back,