Electricity and Magnetism Answers

there is an electric potential of 120V at a point that is 0.25m away from a charge. find the magnitude and the sign of charge

Suppose a telephone linking lagos and london is a copper wire length 6000km.if the current in this wire is 0.6mA,what is the velocity electron of the wire?if telephone impulses were to travel the speed ,how long will it take to transmit a message along the line?estimate the actual time take.The diameter of the wire is 5×10^-4m,the number density of copper atoms is 8 4×10^28m^-3 and the speed em wave is 3×10^8ms^-1.

1. Two charges are arranged so that a -2.5μC charge is placed at the origin and a 1.7μC charge is placed 0.50m to the right.  What is the electric field at (0.50m, 1.0m)

A wire of a certain length is specified to be 200 Ω resistance at 18⁰C what error is caused  in using this wire as a standard on a day when the temperature is 32⁰C? The temperature coefficient of resistance of the specimen is 4 x 10^-3K^-1

 A certain resistor has a resistance of 212.1Ω at 25⁰C and a resistance of 214.2 Ω at 50⁰C. What is its temperature coefficient of resistivity?

   A 12 Ω and an 18 Ω are connected in parallel and the combination connected across 24oW dc line. (a) What is the resistance of the parallel combination? (b) What is the total current drawn by the combination?(c) what current is drawn by each resistor?

1.      4.2 A potential difference of 75V is applied to a combination of 1.25microFarad and 0.6microfarad capacitor connected in series (a) what is the charge on each capacitor? (b) what is the potential difference across the 1.25microFaradcapacitor

A potential difference of 75V is applied to a combination of 1.25microFarad and 0.6microfarad capacitor connected in series (a) what is the charge on each capacitor? (b) what is the potential difference across the 1.25microFaradcapacitor?

Inside the three-dimensional conductor body is an inflatable cavity. What is the electric field in the cavity when the total charge of the conductor is + Q? And what can you say about the potential in the cavity?