Two charged spheres A and B are hung to a point on a ceiling by two identical non-conducting strings. They remain at rest as shown. Which of the following statements MUST be correct?
(1) They will drop and touch each other by bringing an alpha source nearby.
(2) The mass of A is larger than B.
(3) The force acting on A by B is equal to the force acting on B by A in magnitude.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2), (3)
SOS! 20 marks!
I wonder if this question's answer is wrong. Just help me solve this. Many thanks.
更新1:
But the answer is C. I don't know why statement (1) is wrong.
更新2:
But alpha can ionize air molecules and the ions can neutralize the spheres.
