Q.21)-What principle/law explains the working of the hydraulic brakes in automobiles?
  • Bernoulli's law
  • Posieulle's principle
  • Pascal's law
  • Archimedes' principle
Q.22)-An oil drop spreads over water because
  • Oil is lighter than water
  • Oil is more viscous
  • Oil does not mix with water
  • Surface tension of oil is much smaller than that of water
Q.23)-A fountain pen works on the principle of
  • Flow of liquids from higher to lower potential
  • Capillary action
  • Bernoulli's principle
  • Viscosity of liquids
Q.24)-A falling drop of rain water acquires the spherical shape due to
  • Viscosity
  • Surface tension
  • Atmospheric pressure
  • Gravitational force
Q.25)-The weakest of all fundamental forces is
  • Gravitational force
  • Electrosatic force
  • Magnetic force
  • Nuclear force
Q.26)-The modulus of rigidity is the ratio of
  • Longitudinal stress to longitudinal strain
  • Volume stress to volume strain
  • Shearing stress to shearing strain
  • Tensile stress to tensile strain
Q.27)-A spherical ball made of steel when dropped in mercury container will
  • Sink in mercury
  • Will be on the surface of mercury
  • Will be partly immersed
  • Will dissolve in mercury
Q.28)-Damp clothes are dried in spin dryers by the action of
  • Centripetal force
  • Centrifugal force
  • Central forces
  • None central forces
Q.29)-Which of the following is a result of surface tension?
  • Gravitational pull
  • Viscosity
  • Capilllary action
  • Radiation
Q.30)-The wall of a dam is broader at the base
  • Because streamlining is required
  • To withstand pressure that increases with depth
  • To withstand pressure that increases in a horizontal plane
  • To withstand pressure that is increased with atmosphere pressure