Why should spotting of mixture be done above the level of mobile phase ?

Why should we save energy ?

A street light bulb is fixed on a pole 6 m above the level of the street. If a women of height 1.5 m casts a shadow of 3 m, then find how far she is away from the base of the pole.

Why should a photodiode br operated in reverse biased mode?

In activity 2, why does the coin become visible once the level of water reaches a certain height?

When a capillary tube of radius 'r' is dipped vertically in a liquid of surface tension T, the liquid rises to a height 'h' in the tube above the level outside the tube. If the angle of contact is theta , the density of the liquid is rho , then the pressure difference is.

A meter gauge railway track is to be banked at a circular curve of a radius 450m. What should be the elevation of the outer rail above the inner rail for an optimum speed at 54km/h, So that there is no side thrust on the outer rail.

An open glass tube is immersed in mercury in such a way that a length of 8 cm extends above the mercury level. The open end of the tube is then closed and sealed and the tube is raised vertically up by additonal 46 cm. What will be length of the air column above mercury in the tube now? (Atmospheric pressure = 76 cm of Hg

Why should an organism be made of different kind of cells?

Why jockey should not be slided along the potentiometer wire?