Question

A Van de Graaff generator (like the one used in class) has a metal sphere on the top with a radius of 15.0 cm. It is charged to the point where the total charge on the surface of the sphere is +3.50 μC ?

(e) What is the charge on the Van de Graaff generator now?

(f) Suppose that by a “long distance” we mean 2.00 m (this is long enough for our purposes). In other words, the center of the metal ball is 2.00 m away from the center of the Van de Graaff generator. How strong is the force that the Van de Graaff generator exerts on the sphere? Would this likely be noticeable?

(g) In part 1f you had to make an approximation (did you realize you were making an approximation?). If the ball was not a “long distance” from the Van de Graaff generator would have been able to make this approximation? Would you be able to do the calculation of the forces that the objects exert on each other? (Hint: think about part 1c.)

(h) Ions are constantly generated, naturally, in air. This often happens because of cosmic rays or ultraviolet light interacting with the air. Suppose that an N+2 ion is produced near to the metal ball and the Van de Graaff generator. The Van de Graaff generator is at the origin, the metal ball is at 2.00ˆi m and the ion is at 2.00ˆi + 0.300ˆj m. Find the acceleration (vector) of the ion.

Answer 1