Q.41)-Materials for rain proof coats and tents owe their water proof poperties to
- Surface tension
- Viscosity
- Specific gravity
- Elasticity
Q.42)-When two ice cubes are pressed together they join to form one cube. Which one of the following helps to hold them together?
- Hydrogen bond formation
- Vander waals forces
- Covalent attraction
- Dipole interaction
Q.43)-When a piece of stone is immersed in water it displaces water of equal
- Density
- Specific gravity
- Mass
- Volume
Q.44)-The minimum number of forces to keep a particle in equllibrium is
- 1
- 2
- 3
- 4
Q.45)-Purity of a metal can be determined with the help of
- Pascal's law
- Boyle's law
- Archimedes priciple
- Conservation of mass principle
Q.46)-In a particular system, the units of length, mass and time are chosen to be 10 cm, 10 g and 0.1 s respectively. The unit of force in this system will be equivalent to
- 0.1 N
- 1 N
- 10 N
- 100 N
Q.47)-The weight of a body at the centre of earth is
- Half the weight at the surface
- Zero
- Twice the weight at the surface
- Infinite
Q.48)-On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because
- Mercury is a metal
- Density of mercury is greater than that of water
- Cohesion of mercury is greater than its adhesion with glass
- Cohesion of water is greater than its adhesion with glass.
Q.49)-Name the process by which bubbles from liquid are formed?
- Effervescence
- Surface tension
- Surface energy
- Degasification
Q.50)-The wasing machine works on the principle of
- Dialysis
- Diffusion
- Reverse osomosis
- Centrifugation