Discuss about the machines employed for resistance welding.
Make a distinction between A.C and D.C welding
Illustrate about the techniques employed for arc welding.
State and describe laws of Illumination.
A lamp having the uniform cp of 200 in all directions is provided with a reflector which directs 60% of the light uniformly on to a circular area of 10 m diameter. The lamp is hung 6m above the area. Compute the illumination at (i) the centre (ii) the edge of the surface with and devoid of reflector. Find out the average illumination over the area without the reflector.
Illustrate the construction and working of the MV lamp.