Assertion (A) All liquids are conductors of electricity.Reason (R) Under the condition of low pressure and high voltage, liquids can be made conducting.
Assertion (A) Light shows the phenomena of interference, diffraction and polarization,Reason (R) Because light behaves as corpuscles.
Assertion (A) A dentist uses a concave miror to examine a small cavity.Reason (R) A dentist uses a concave mirror which can form a magnified virtual image of an object.
Assertion (A) Internal energy of an ideal gas does not depend upon volume of the gas.Reason (R) This is because internal energy of ideal gas depends on temperature of gas.
Assertion (A) On a rainy day, it is difficult to drive a car or bus at high speed.Reason (R) The value of coefficient of friction is lowered due to wetting of the surface.
Assertion (A) The velocity of sound in air increases due to the the presence of moisture in it.Reason (R) The presence of moisture in air lowers the density in air.
Assertion (A) The covalent bond is formed by the sharing of pairs of electrons between atoms.Reason (R) Covalency is greatest between atoms of different electromagnetism.
Assertion (A) The ships of iron and the boats of wood float in water but the nails iron sink.Reason (R) The special design and shape of the ship and the boat through which weight of the ship and boat, due to which more than the weight of the ship and boat, due to which more force of buoyancy becomes operative and the ships or boats floats. But the weight of the water displaced by the nails is less than the weight of nails that is why nails sink.
Assertion (A) Water kept in an open vessel will quickly evaporate on the surface of the moon.Reason (R) The temperature at the surface of the moon is much higher then boiling point of water.
Assertion (A) As solid changes to liquid and then to vapour state, entropy increases.Reason (R) As going from solid to liquid and then to vapour state, disorder increases.