Electricity and Magnetism Answers

A flat coil with 78 loops of wire has a radius of 15 mm. The coil is placed in a magnetic field of 0.35 T so that a maximum flux goes through it. It is later rotated in 0.07 s to a position so that no flux can go through. What is the average induced EMF produced between the terminals of the coil?

2. An infinitely long wire that has a radius of 3 cm contains a uniform charge density of 15 μC/m². Determine the total charge present in a 3.0-m long section of the copper wire and the magnitude of the electric field at a distance of 12 m from the wire.

What charge is stored in a 180 μF capacitor when 120 V is applied to it?

 Two identical metallic spheres are suspended as bobs of a simple pendulum. Each of the bobs has a charge of  If each string is 1m long and makes an angle of 12 degrees to the vertical, (a) what is the electric force between the spheres? (b) The bobs touched each other and then separated. What then is the electric force between the sphere?

​(I) Four point charges are located at the vertices of a square with side L.

We give q2 ​= q3 ​= Q and q1​= q4 ​= −2Q.

​Determine the resulting electric field​ (a) at point A​,

in the center of the square; (b) at point B

A triode passes a plate current of 5mA at plate voltage 150V and grid voltage of -2V. If the grid voltage is changed to -35V, the plate current drops to 3.2mA but can be restored to 5mA by increasing plate voltage to 195V. Calculate

(1) mutual conductance

(2) a.c. plate resistance

(3) amplification factor

how did the size of the current in the coil affect the strength of the electromagnet

A point charge Q1 at x= 1 m and a charge Q2 at x= d. What is the relationship between these charges if the resulting electric field is zero at the following points: a) x= d/2 b) x= 2d c) x= -d/2?

(Answer: a) Q1/Q2= 1 b) Q1/Q2= -4 c) Q2/Q1= -9)

A point particle of charge 2.5nC and mass 3.25x10^-3 kg is in a uniform electric field directed to tje right .It is released from rest and moves to the right.After it has traveled 12.0cm,its speed is 25 m/s. Find the

a) work done on the partcle

b) change in tje electric potential energy of the particle and

c) magnitude of the electric field.

Calculate the electric flux for each of the closed surfaces a,b,c and d.