11.Which of the following substances has the highest value of the Youngs modulus?

12.A wire is stretched 1 mm by a force of 1 kN. How far would a wire of the same material and length but of four times that diameter be stretched by the same force ?

13.When a rubber cord is stretched, the change in volume with respect to change in its linear dimensions is negligible. The Poisson s ratio for rubber is

14.When a certain weight is suspended from a long uniform wire, its length increases by one cm. If the same weight is suspended from another wire of the same material and length but having a diameter half of the first one, the increase in length will be

15.Four wires of the same material are stretched by the same load. The dimensions of the wires are as given below. The one which has the maximum elongation is of: