Field Theory Answers

 Each of two parallel horizontal wires, running east-west, are seperated by 0.89 m, has a current of 4.8 A. Wire 1 lies North of Wire 2.  Calculate the magnitude and direction of the magnetic field midway between the two wires if: a) The current is directed east in Wire 1 and west in Wire 2. (b) The current is directed east in both wires.  Be sure to clearly explain your results. HINTS:  (1) Magnetic field strength is a vector, so can be added/subtracted based on direction.  (2) Consider the left hand rule for a straight wire to determine direction.

 A long solid copper rod has a circular cross section of diameter 15.76 cm. The rod carries a current of 6.41 A, uniformly distributed across it's cross section.  Calculate the magnetic field strength: (a) at the centre (b) 3.94 cm from the centre (c) 7.88 cm from the centre, and (d) 11.82 cm from the centre.

What is the magnitude of the force acting on a straight wire of length 1.029 m, with a current of 8.71 A, and inclined at an angle of 23.44 degrees to a uniform magnetic field of magnitude 0.692 T?

What length of conductor, placed at right angles to a magnetic field of magnitude 0.052 T, and with a current of 16.04 A, experiences a force of 1.013 N?

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.

 Two small objects (A and B) each has a mass of 17.0 kg.  They are located in interstellar space and separated by a distance of 1.016 km.  Object A has a charge of -5.3 C and Object B has a charge of +3.7 C.  (a) Assuming the direction towards each other is positive, determine the acceleration of Object A.  (b) Re-calculate your answer to (a) ignoring gravitational force, what can you say about the effect of gravitational force? (c) What does the magnitude of the acceleration tell you about electric force?

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