Physics Past Questions and Answers

A small steel needle is carefully floated on water in a beaker. When a few drops of kerosine are introduced into the water the needle sink. Which of the following statements correctly explain(s) the observation? i. there is tension on the water surface ii. kerosine reduces the density of water so that needle becomes denser than water iii. kerosine reduces the surface tension of water

Which of the following statements describes an atom accurately? i. atoms of all elements are identical ii. an atom contains a nucleus and number of electrons iii. due to the electrons in the atom an atom is negatively charged iv. electrons in the atom move in circular orbits round the nucleus

A particle moves in a circular orbit of radius 0.02m. If the speed of the particle is 0.88ms<sup style='font-size: smaller;'>-1</sup>, calculate its frequency in cycles per second

Heat is supplied uniformly at the rate of 100W to 1.0 x 10<sup style='font-size: smaller;'>-2</sup>kg of a liquid for 20 seconds. If the temperature of the liquid rises by 5<sup style='font-size: smaller;'>o</sup>C, then the specific heat capacity of the liquid is

A given mass of an ideal gas occupies a volume V at a temperature T and under a pressure p. If the pressure is increased to 2p and the temperature reduced to \(\frac{1}{2T}\), then the percentage change in the volume of the gas is