Answer:
d)
Explanation:
Electrons are lost or gained when the ballon is rubbed with a PVC. As the rubber ballon lost electrons, it will have more protons, hence the positive charge. (More protons than electrons in the ballon).
Answer:
Point number 3.
Explanation:
Volcanism can be studied to found out evidence of the internal structure of the Earth.
Missing questions: "find the speed of the electron".
Solution:
the magnetic force experienced by a charged particle in a magnetic field is given by

where
q is the particle charge
v its velocity
B the magnitude of the magnetic field

the angle between the directions of v and B.
Re-arranging the formula, we find:

and by substituting the data of the problem (the charge of the electron is

), we find the velocity of the electron:
The answer, using an indicator to measure the hydrogen ion concentration of a solution, is correct