Electricity and Magnetism Answers

11. The e.m.f. of an element is 6 V. When the external resistance is 1.1 Ohm the current in the circuit is equal to 3 A. Find the potential drop inside the element and its resistance.

13. A capacitor with a capacitance of 20 mkF is charged to a potential of 100 V. Find the energy of this capacitor.

Find the capacitance of the Earth. The radius of the Earth is 6,400 km. By how much will the Earth's potential change if it receives a quantity of electricity equal to 1 C?

A ball with a mass of 1 gramme and a charge of 10^-8 C moves from point A whose potential is 600 V to point B whose potential is zero. What was the velocity of the ball at point A if at point B it is 20 cm/s?

What force does the electric field of a charged infinite plane act with on each metre of a charged infinitely long filament placed in this field? The charge linear density on the filament is 3x10^- 8 C/cm and its surface density on the plane is 2x10^-8 C/cm2.

What force does the electric field of a charged infinite plane act with on each metre of a charged infinitely long filament placed in this field? The charge linear density on the filament is 3x10- 8 C/cm and its surface density on the plane is 2x10-8 C/cm2.

The coordinate-free form of electric field at an arbitrary point P (a distance r away). of an electric dipole located at the origin is E(r)= 1 4 pi epsilon 0 [ 3(p.r) r^ 3 r- p r^ 3 ] Convert this into an expression in spherical coordinales.

12. Find the potential drop along a copper wire 500 m long and 2 mm in diameter if the current in it is equal to 2 A

Two charges lie in a line along the x axis. Charge 1 is q1 = 0.65 C and charge 2 is q2 = 2.45 C. They are each a distance of d = 0.021 m from the origin.

What is the distance on the x-axis from the origin at which the electric field will be zero. Give your answer in meters.

A 50 Hz sinusoidal voltage has rms value of 200 V. At t=0, the instantaneous value is positive and half of its maximum value. Write down expression for voltage and sketch the waveform