A luminous object is one that

Which of the following units is not fundamental?

The vacuum between the double walls of a thermos flask reduces heat loss through

 In photoelectric effect, the number of electrode emitted per second from a metallic surface is proportional to the

When two cells of negligible internal resistances and equal e.m.f. denoted by E\(_1\) and E\(_2\) are connected in parallel, combined e.m.f. E is given by