Consider two wires X and Y. The radius of wire X is 3 times the radius of Y. If they are stretched by the same load then the stress on Y is

(a)

equal to that on X

(b)

thrice that on X

(c)

nine times that on X

(d)

Half that on X

The load – elongation graph of three wires of the same material are shown in figure. Which of the following wire is the thickest?

(a)

wire 1

(b)

wire 2

(c)

wire 3

(d)

all of them have same thickness

A small sphere of radius 2cm falls from rest in a viscous liquid. Heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity is proportional to

(a)

2²

(b)

2³

(c)

2⁴

(d)

2⁵

With an increase in temperature, the viscosity of liquid and gas, respectively will

(a)

increase and increase

(b)

increase and decrease

(c)

decrease and increase

(d)

decrease and decrease

Which of the following is not a scalar?

(a)

viscosity

(b)

surface tension

(c)

pressure

(d)

stress