Q.11)-Magnetism at the centre of a bar magnet is
  • minimum
  • maximum
  • zero
  • minimum or maximum
Q.12)-Inside an aeroplane, flying at a high altitude
  • the pressure is the same as that outside
  • normal atmospheric pressure is maintained by the use of air pumps
  • the pressure inside is less than the pressure outside
  • normal humidity and partial vacuum are maintained
Q.13)-It is more difficult to walk on a sandy road than on a concrete road because
  • sand is soft and concreter is hard
  • the friction between sand and feet is less than that between concrete and feet
  • the friction between sand and feet is more than that between concrete and feet
  • the sand is grainy but concrete is smooth
Q.14)-Of the following properties of a wave, the one that is independent of the other is its
  • amplitude
  • velocity
  • wavelength
  • frequency
Q.15)-Lux is the SI unit of
  • intensity of illumination
  • luminous efficiency
  • luminous flux
  • luminous intensity
Q.16)-On a rainy day, small oil films on water show brilliant colours. This is due to
  • dispersion
  • interference
  • diffraction
  • polarization
Q.17)-Materials for rain-proof coats and tents owe their water-proof properties to
  • surface tension
  • viscosity
  • specific gravity
  • elasticity
Q.18)-RADAR is used for
  • locating submerged submarines
  • receiving a signals in a radio receiver
  • locating geostationary satellites
  • detecting and locating the position of objects such as aeroplanes
Q.19)-Sound of frequency below 20 Hz is called
  • audio sounds
  • infrasonic
  • ultrasonic
  • supersonics
Q.20)-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