A physicist is equipped to measure electric, magnetic, and gravitational fields. Which will he/she detect?

Question

when a proton moves past them? When they move past a proton?

Answer 1

You should be able to measure all three, in both cases.. limited only by the sensitivity and accuracy of your instruments.

when a particle with mass moves past you, or you move past it, the force excerted by gravity between you and the particle changes with distance. Of course you need to have a mass too. and your instruments need to be good enough to distinguish these forces from other gravitational and other kind of forces.

If a charged particle moves, it produces a magnetic field. this is the same effect as seen in a elecromagned where moving elecrons produce magnetic fields.

if a charged particle moves past you, and you have a detector that is based on charge too, you will notice an increase or decrease in attractive or repulsive force between your detector and the charged particle as the distance between the both changes. again this force is miniscule and is easily confused with other stray forces including the above gravitational ones.

Answer 2

He/she could measure three of them.And when a proton moves he/she could detect both the magnetic&the electric field.

Answer 3

Electric and magnetic in both cases. Gravity is too weak to measure unless the instrument is extremely sensitive.

Answer 4

All of them.

All very tiny.