Field Theory Answers

Ferd charges an ebonite rod, which always becomes negative, with a charge of 23.7 nC.  The magnetic field in the lab is 4.53E-5 T[North]. Ferd throws with a velocity of 4.8 m/s[West]. What is the resulting magnetic force? Show how you got your answer for both magnitude and direction.

 Calculate the electric potential and magnitude of electric field strength 0.378 m from a small sphere with 6.0E10 excess electrons.

A metallic table tennis ball of mass 0.127 g has a charge of 7.3E-6 C.  What potential difference is required to hold the table tennis ball in suspension across a large parallel plate apparatus with plate separation of 20.0 cm.

 A ping pong ball of mass 4.686E-4 kg, hangs from a light thread 1.0 m long between two vertical parallel plates 10.0 cm apart. When the potential difference across the plates is 416.0 J/C, the ball comes to equilibrium 1.1 cm to one side of its original position. (a) Calculate the electric field strength between the plates. (b) Calculate the tension in the thread (c) Calculate the magnitude of the electric force acting on the ball (c) Calculate the charge on the ball. Note, please neglect any vertical deflection of the ball.

Calculate the total flux passing through each face of the cube for a charge of 5 micro coulomb which is placed 5cm above the lower face of the cube whose side length is 1 cm

What potential difference is required to accelerate a proton from rest to a speed of 5.72E7 m/s?

 An electron enters a parallel plate apparatus as seen in Figure 7 with an initial velocity of 2.05E6 m/s. The magnitude of the electric field strength across the plates is 237.7 N/C and the length of the plates is 7.08 cm. Determine the exit velocity of the electron.

The parallel plate apparatus in Figure 6 accelerates electrons across a potential difference of 2963.6 V. Determine the speed with which the electron reaches the positively charged plate.  (b) How could this apparatus be modified to accelerate protons?  (c) If a proton was accelerated instead of an electron, with what speed would it reach the negative plate?

Two equally charged objects of mass 1.68 kg are located 0.08 m apart.  Determine the possible charges on the objects if the net force on each of them is zero.

An electric charge of 8.85 x 10-13 C is placed at the centre of a 

sphere of radius 1m. What is the total electric flux linked with the 

sphere? How will the electric flux change if another equal and 

dissimilar charge is introduced at a distance of (i) 0.5m from the 

centre, (ii) 1.5m from the centre?