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