[{"id":15568,"question":"When a Na ion and a CI ion are placed in air a force F acts between them when they are separated by a distance of 1 cm from each other the permittivity of air and the dielectric constant of water are&nbsp;ε<sub>0</sub> and K respectively When a piece of salt is placed in water then the force between Na<sup>+</sup> and CI<sup>-</sup> ions separated by a distance of 1 cm will be","choices":[{"text":"F","value":"A"},{"text":"FK/ε<sub>0</sub>","value":"B"},{"text":"F/Kε<sub>0</sub>","value":"C"},{"text":"F/K","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":15567,"question":"Two point charges placed at distance of 20 cm in air repel each other with a certain force.When a dielectric slab of thickness 8 cm and dielectric constant K is introduced between these point charges force of interaction becomes half of its previous value Then K is approximately.","choices":[{"text":"2","value":"A"},{"text":"4","value":"B"},{"text":"√2","value":"C"},{"text":"1","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":15566,"question":"A point charge Q is placed at the mid-point of a line joining two charges 4q and q. if the net force on charge q is zero. then Q must be equal to","choices":[{"text":"-q","value":"A"},{"text":"+q","value":"B"},{"text":"-2q","value":"C"},{"text":"+4q","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":15565,"question":"In a Millikan's oil drop experiment the charge on an oil drop is calculated to be 6.35 x 10-19 C. The number of excess electrons on the drop is","choices":[{"text":"3.9","value":"A"},{"text":"4","value":"B"},{"text":"4.2","value":"C"},{"text":"6","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":15564,"question":"Two point charge +3μC and +8μC repel each other with a force of 40 N. if a charge of -5μC is added to each of them then the force between will become","choices":[{"text":"-10N","value":"A"},{"text":"+10N","value":"B"},{"text":"+20N","value":"C"},{"text":"-20N","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":15563,"question":"What is the average energy of N molecules of monoatomic gas?","choices":[{"text":"1/2 NkT","value":"A"},{"text":"NkT","value":"B"},{"text":"3/2 NkT","value":"C"},{"text":"5/2 NkT","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":15562,"question":"What is the ratio of r.m.s velocity for O<sub>2</sub> to H<sub>2</sub>?","choices":[{"text":"1/4","value":"A"},{"text":"4","value":"B"},{"text":"√4 : 1","value":"C"},{"text":"1 :&nbsp;√4","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":15561,"question":"At 0° K which of the following properties of a gas will be zero?","choices":[{"text":"Kinetic energy","value":"A"},{"text":"Potential energy","value":"B"},{"text":"Vibrational enegy","value":"C"},{"text":"Density","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":15560,"question":"The product of the pressure and volume of an ideal gas is","choices":[{"text":"A constant","value":"A"},{"text":"Approximately equal to the universal gas constant","value":"B"},{"text":"Directly Proportional to its temperature","value":"C"},{"text":"Inversely proportional to its temperature","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":15559,"question":"Boyle's law is applicable in","choices":[{"text":"Isochoric process","value":"A"},{"text":"Isothermal process","value":"B"},{"text":"Isobaric process","value":"C"},{"text":"Isotonic process","value":"D"},{"value":"E"}],"correctAnswer":2}]