Electricity and Magnetism Answers

Find the work done in bringing the charge q0 from infinity to any point at a distance r in the field of charge q

can we say that LIGHT is a matter?

A magnetic field in a certain region is given by B=B°cos(wt) + z axis and a coil of radius a with resistance R is placed in the x-y plane with it's centre at the origin in the magnetic field. Find the magnitude and direction of the current at (a,0,0)at t=π\2w.

if we have 2 parallel plates for which one is at positive 2.0 kV and the other at positive 6.0kV,
I wanted to know, what does it mean for those two voltages being positive ? and how is voltage of those plates even increased ? what happens inside the material and what is this voltage that it receives? in the form of what ?

How does an earthed metal plate attract a positive charge if it is said to be neutral, I saw a diagram and the field lines of that positive charge were directed at the plate.

Why is that earthed metal plate uncharged ? if its electrons escape into the ground it has more positive charges and so does have a charge

I read that an earthed metal plate has zero volts. Does that mean that any object that is charged like a pen for example has some kind of voltage ? And if so I really dont understand what it means for an object to have a voltage and how is it increased what happens inside that object ?

given a coaxial cable of length 30 centimeter with inner radius 1 millimeter and 4 millimeter respectively, the space between the conductors is assumed to be filled with air. the total charge on the inner conductor is 1 nano coulomb. find the charge density on each charge and also the internal field

In practical experiment inloving the use of optical pins, parallax is reduced or removed if on slightly displacing one's eye from side to side

The company that you work for produces a range of power supplies which are supplied
in large quantities to businesses that manufacture computers and IT equipment. More
range of power supplies is being added and the company has developed a 50W unit.
From the first batch of 1000 units a 10% sample has been taken and the power output
of each unit tested shown in Table 2(a). Using this data calculate the mean, median
and mode, explaining the significance of each.
PS50 50W Nominal rating
Power output Number
49.60–49.69 1
49.70–49.79 1
49.80–49.89 4
49.90–49.99 7
50.00–50.09 19
50.10–50.19 31
50.20–50.29 21
50.30–50.39 8
50.40–50.49 5
50.50–50.59 2
50.60–50.69 1

charging and discharging characteristics of DC
(a) Here is the information about the circuit.
Capacitor = 100 nF , Resistor = 47 kΩ ,Supply voltage = 5 V
Charging characteristic for a series capacitive circuit:
v=v(1 − e−t/RC)

 Investigate what the other terms in this expression mean.
 Calculate the time constant for the circuit.
 Use a spreadsheet to plot the charging curve over the range 0 to
20 ms (milliseconds).
 Investigate the meaning of ‘time constant’ and from your graph
estimate a value. Compare this with your calculated one.
 Differentiate the charging equation and find the rate of change of
voltage at 6 ms.
 From your graph measure the gradient at 6 ms and compare this with
the calculated value.

(b) Now investigate the discharging characteristic of the circuit but with a 22 kΩ resistor
fitted.

 Calculate and estimate the rate of change of voltage when t = T.

Electron move with an initial speed of 4×10^7 m/s. enter perpendicular 0.1T magnetic field
a. Exolain the particles traces
b. Find the circle radius