Physics Past Questions and Answers

Which of the following surfaces will radiate heat energy best?

A Red
B White
C Black
D Yellow
E Blue

Question 87:

Which of the followiempeng statements is/are not correct?

A Evaporation takes place only at the surface of the liquid
B Boiling takes place throughout the volume of the liquid
C Evaportaion takes place at all temperatures
D Boiling takes place at a particular temperature for a liquid at a fixed external pressure
E The boiling point of a liquid is not affected by impurities

Question 88:

Water in an open container boils at a lower temperature when heated at the top of a mountain than at sea-level because at the top of a mountain the

A Relative humidity is higher than at sea-level
B Rays of the sun adds more heat to the water
C Temperature is lower than that at sea-level
D Pressure is lower than that at sea-level
E Pressure is more than that at sea-level

Question 89:

Which of the following substance is not a good conductor of electricity?

A Human body
B Glass
C Aluminium
D Earth
E Copper

Question 90:

Calculate the heat energy required to vapourize 50g of water initially at 80^oC if the specific heat capacity of water is 4.2Jg^-1K (specific latent heat of vapourization of water is 2260Jg^-1).

A 533000J
B 230000J
C 117200J
D 113000J
E 4200J