Electricity and Magnetism Answers

An oil drop of average diameter 0.7mm spreads out into a roughly circular patch of diameter 75cm. On the surface of water in a trough. Calculate the average diameter of a molecule of oil

In Finland, steel-reinforced aluminum conductors with a total cross-sectional area of ​​3.4 cm ² are used in 110 kV power transmission lines. In this case, the power losses are less than 2%. How large should the cross-sectional area of ​​the conductor be in order for the 400 V transmission voltage to achieve as small power losses as for the 110 kV voltage when the transmitted power is the same?

The primary winding of the welding transformer has 1000 turns and the secondary winding 110 turns. It is connected to the mains at a voltage of 230 V, giving a secondary current of 120 A. Assume an ideal welding transformer.

a) What is the primary current? How big a fuse should there be behind the socket to which the welding transformer is connected - which of the 10 A, 16 A or 20 A fuses is large enough?

b) What is the secondary voltage?

c) Why is the secondary current in the welding transformer desired high?

4. Show that 5 · ~ (fA~) = f5 · ~ A~ + A~ · 5~ f (Problem 1.16, P Lorrain & D

Corson)

3. Among the following which can not be an electric field? E~ = c(xyi +2yzj +3xzk), E~ = c(y^2i + (2xy + z^2)j + 2yzk), where c is a constant.

What would be the dimension of c? (Problem 2.20 of Griffiths, 4th

edition)

2. Using Levi-Civita symbol, prove (A~ ×B~ )·C~ = (B~ ×C~ )·A~ = (C~ ×A~)·B~

1. Verify Stock’s theorem for F~ = x^2i+xyj, where s is the area bonded by

a triangle whose vertices are at (0, 0), (1, −1) and (1, 1), respectively.

dear sir it says line spectrum has 2 element of absorption spectrum and emission spectrum and also it says these 2 elements can be applied to continuous spectrum too what is the meaning of that please help?

A positively charged particle of charge q moves with velocity 𝑣⃗ in a uniform magnetic field of flux density 𝐵⃗⃗. With plausible mathematical treatment, determine the work done on the particle and the kinetic energy of the particle.