physics document

1. PACA FOUNDATION CLASSES
. All questions are compulsory.
PART-A
.Use appropriate answer.
Q1-In a solid, heat is transferred mainly by the process of:
(a) Conduction (b)convection
(b) Radiation (d)none
Q2-A good conductor of heat is:
(a) wood (b)asbestos
(c) air (d) mercury
Q3-In a liquid, heat is transferred mainly by:
(a)conduction (b)convection
(c) radiation (d)none
Q4-in convection, heat is transferred:
(a) upwards (b)downwards
(c) sideways (d)in all directions.
Q5-In vacuum heat is transferred by:
(a)conduction (b) convection
(c) radiation (d)none.
Q6-The fastest mode of transfer of heat:

2. (a)Radiation (b)convection
(c) conduction (d)none.
Q7-Heat loss from surface by radiation can be reduced by:
(a) keeping it in dark.
(b) blackening the surface.
(c) polishing the surface.
(d)keeping the surface in vacuum.
Q8-In a thermos flask, the vacuum between its walls reduce the heat loss by:
(a)conduction (b)convection
(c)radiation (d)conduction, convection both.
PART-B
Q1. Name the different modes of the transfer of heat.
Q2. What is good bad conductor of heat? Give two example of each.
Q3.Arraange the following in order of their increasing heat conductivity:copper,
air, water, mercury.
Q4. Explain the process of conduction in solid.
Q5.How does the process of conduction differ in metals and non metal.
PART-C
Q1-Name a metal which is a good conductor of heat.
Q2-Name a substance which is a good insulator of heat.

3. Q3- Give the list of some common substance in order of their decreasing
conductivity of heat.
Q4-In winter, a piece of iron on being touched by hand appears colder than a
piece of wood. Give reason.
Q5- when a metallic wire gauze is brought over the frame of a burner,the flame
does not pass through the wire mesh. Give reason.
Q6-Explain briefly the process of heat transfer by convection.
Q7-In a solid ,heat is not transferred by the process of convection.Give reason.
Q8-It is possible to heat a liquid or gas? Explain in your words.
Q9-Why is a room heater in a room installed near the floor of the room.
Q10-By the process convection ,heat is always transferred vertically upwards.Give
reason.
Q11-the inside of a closed car parked In the son is much warmer.Explain.
Q12-On opening the windows of a glass walled room, the insight temperature
falls. Explain.
Q13- A red hot iron wall a suspended from the celling of a room by a thin metallic
wire.
(a)Name the ways In which the ball losses heat.
(b)Name the way by which it losses the heat least, given a reason for your answer.
(c)Explain what role the air in the room plays in the loss of heat.
Q14-Name the three process of the heat transfer and distinguish between them.
Q15-What is green house effect ,name three green house gases.
Q16-what is ecosystem.
Q17-Draw carbon cycle.