Question

# A proton is accelerated through a potential difference of 10 kV and enters a uniform magnetic...

1. A proton is accelerated through a potential difference of 10 kV and enters a uniform magnetic field at right angles. Calculate the value of the magnetic flux density necessary to move the proton in a circular path of radius 10 mm. 
1. A piece of wire of cross-sectional area A and resistivity ρ is bent into a circular loop of radius r and placed in a magnetic field with its plane at right angles to the field. Determine the magnitude of the current in the loop if the field is reduced to zero in time t. 

1. A 40 μF capacitor is charged to a voltage of 120 V. How much work must be done to transfer 60 μC from the negative plate to the positive? 

1. A point charge of magnitude +q and speed v is located at a distance d from a long straight wire carrying a current I.

(a) Determine the magnitude of the force on the charge if it is moving directly towards the wire. 

(b) Is the direction of the force parallel or anti-parallel to the wire? Use a fully labeled sketch to motivate your answer.  