1. Metals expand on heating and contract on cooling.   True   False   2. The wire of an electric bulb is known as the   Heating Element   Radiator   Luminous Wire   Filament   Hint Half-n-half Clue   3. The high pitched cries of a bat are above human hearing.   True   False   4. The presence of charge on a substance can be confirmed by a   Electrodes   Thermometer   Ammeter   Gold Leaf Electroscope   Half-n-half Clue   5. What is the speed of sound in air in meters per second (at a pressure of one atmosphere and temperature of 25oC)?   110   490   330   230   Half-n-half Clue   6. By which of the following methods does heat transfer not take place?   Conduction   Convection   Radiation   Refraction   Half-n-half Clue   7. What is the name of the point where light rays from infinity coverge after passing through a lens?   Focus   Center   Parabola   Infinity   Half-n-half Clue