Electric Circuits Answers

the mathematical comparisons of energy/power loss of transmitting electricity at different voltages

Describe how AC electricity is transferred from the hydroelectric plant to homes and industry. Mathematically account for the need of transformers and high voltages. You should include:

a reasoned argument as to why a high voltage AC generator should be used rather than a low voltage turbine driven dynamo

Compare the formula ∆V=ε∆d and ∆V=(kq/r1) – {kq/r2). Explain the meaning of each symbol and
under what conditions can each formula be used.

The Bainbridge-type mass spectrometer uses a velocity selector to select only those ions with the
proper velocity. The selector has two charged parallel plates to create an electric field pointing down,
and copper coils to create a magnetic field. Electrons (q=-1.6x10-19) with speed 5x104 m/s should
pass through the selector with velocities directed to the right without changing direction.
a) In which direction should the magnetic field pointing to?
b) How large should be the magnetic field if the electric field strength is 7000 N/C.
c) What would happen to an electron that has the speed of 7.5x104 m/s?

Using your AC graph, add an appropriate scale on the vertical axis and label the ‘peak voltage value’ and ‘RMS voltage value’. Explain why RMS voltage value is more useful than the peak value. Show, by calculation, the peak voltage value if the effective voltage value in the UK is 230V.

It is essential that the smelting works protects its workers by applying the Electricity at Work Regulations 1989. Discuss the specific actions that should be taken and the safety devices that should be used to protect workers when operating and repairing plant

Describe how AC electricity is transferred from the hydroelectric plant to homes and industry. Mathematically account for the need of transformers and high voltages. You should include:

a reasoned argument as to why a high voltage AC generator should be used rather than a low voltage turbine driven dynamo

1. A bar magnet falls through a circular loop.
a) Describe qualitatively the change in magnetic flux through the loop when the bar magnet is above and below the loop.
b) Make a qualitative sketch of the graph of the induced current in the loop as a function of time, choosing I to be positive when its direction is counterclockwise as viewed from above.