Though the temperature inside lighted electric bulb is around 2700°C, the filament does not burn because _____.

1. 1. It does not burn in closed system
   2. The oxygen necessary for combustion (and burning) is not available as the bulb is evacuated and filled with pure nitrogen or inert gases
   3. The metal of which it is made is resistant to burning
   4. It is made of non-metallic substance

A cyclist negotiating a bend, tilts from the vertical direction because of _____.

1. 1. Friction and centrifugal force
   2. Gravitation and friction
   3. Gravitation and centrifugal force
   4. Gravitation and centrifugal force

The phenomenon of mirage is due to _____.

1. 1. polarisation of light on reflection
   2. total internal reflection
   3. absorption of light by air at higher temperature
   4. change in refractive index of air with change in temperature

Which one of the following represents a chemical change?

1. 1. Heating of mercuric oxide powder
   2. Heating a platinum wire in a bunsen flame
   3. Evaporation of alcohol
   4. Sublimation of iodine

Fat is digested in the _____.

1. 1. mouth
   2. large intestine
   3. spleen
   4. small intestine

A solid ball of metal has a spherical cavity inside it. If the ball is heated, the volume of the cavity will _____.

1. 1. remain unaffected
   2. have its shape changed
   3. decrease
   4. increase

Semi-conductor is such a substance, whose ability to conduct current lies in between _____

1. 1. Insulators and superconductors
   2. Wood and plastic
   3. Conductors and insulators
   4. Conductors and superconductors

John Walker invented _____.

1. 1. Safety match
   2. Safety pin
   3. Safety razor
   4. Safety valve

The plant which bears fruit only once in its lifetime is _____.

1. 1. Date
   2. Banana
   3. Grapes
   4. Papaya

Amnesia is related to _____.

1. 1. Loss of hearing
   2. Loss of memory
   3. Loss of Teeth
   4. Sleeping sickness