Explain (i) ducitile materials (ii) brittle materials and (iii) elastromers.

In the figure shown the straing versus stress graph for two values of young's modulus ? (i) which material is more ductile ? Explain. (ii) Which material is more brittle ? Explain. (iii) Which material is stronger ? Explain.

Define resistivity of the material. State its SI unit and discuss its variation with temperature in case of (i) metals (ii) semiconductors and (iii) insulators.

Distinguish between ductile and brittle materials on the basis of stress-strain curve

In an ecosystem : (i) the flow of energy is unidirectional (ii) the flow of materials is unidirectional (iii) the flow of materials is cyclic (iv) the flow of energy is cyclic.

The barrier potential of a p-n junction depends on : (i) type of semiconductor material (ii) amount of doping (iii) temperature. Which is one of the following is correct?

A certain radioactive material is known to decay at a rate proportional to the amount present. If initially there is 50 kg of the material present and after two hours it is observed that the material has lost 10% of its original mass, find () and expression for the mass of the material remaining at any time t, (ii) the mass of the material after four hours and (iii) the time at which the material has decayed to one half of its initial mass.