30 is the correct answer your looking for
(D) That's where the Pacific and North American plates meet.
Answer:
C) at right angles to the direction of the motion
Explanation:
The magnetic force exerted on a charged moving particle is given by

where
q is the charge of the particle
v is the velocity of the particle
B is the magnetic field intensity
is the angle between the direction of v and B
Moreover, the direction of the force is perpendicular to both v and B. In particular, the direction can be found by using the right hand rule:
- index finger: direction of the velocity
- middle finger: direction of the magnetic field
- thumb: direction of the force (if the charge is positive, otherwise the direction must be reversed if the charge is negative)
9/3= 3 ampere.. that would be the aswer
Answer:
a)The approximate radius of the nucleus of this atom is 4.656 fermi.
b) The electrostatic force of repulsion between two protons on opposite sides of the diameter of the nucleus is 2.6527
Explanation:

= Constant for all nuclei
r = Radius of the nucleus
A = Number of nucleons
a) Given atomic number of an element = 25
Atomic mass or nucleon number = 52


The approximate radius of the nucleus of this atom is 4.656 fermi.
b) 
k=
= Coulombs constant
= charges kept at distance 'a' from each other
F = electrostatic force between charges


Force of repulsion between two protons on opposite sides of the diameter



The electrostatic force of repulsion between two protons on opposite sides of the diameter of the nucleus is 2.6527