# PTB 9th Class Physics Chapter 9 Solved Questions and Numericals Problems

View and Download the solved questions, solved numerical problems or 9th Class Physics notes of Chapter 9 “Transfer of Heat” of Punjab Textbook Board. These 9th class physics notes of 9th Chapter are according to the new syllabus (2013) of Punjab Boards including Lahore Board, Gujranwala Board, Sahiwal Board, Rawalpindi Board, Faisalabad Board, Multan Board, Bahawalpur Board, Federal Board, DG Khan Board and Sargodha Board. Students of 9th Class of all these board can facilitate from the physics notes given below. You can also download 9th Class Physics Chapter 9 Solved Questions and Numericals Problems.

### Unit 9: Transfer of Heat

By studying this chapter students will be able to: Recall that thermal energy is transferred from a region of higher temperature to a region of lower temperature. Describe in terms of molecules and electrons how heat transfer occurs in solids. State the factors affecting the transfer of heat through solid conductors and hence, define the term Thermal Conductivity. Solve problems based on thermal conductivity of solid conductors. Write examples of good and bad conductors of heat and describe their uses. Explain the convection currents in fluids due to difference in density. State some examples of heat transfer by convection in everyday life. Explain insulation reduces energy transfer by conduction. Describe the process of radiation from all objects. Explain that energy transfer of a body by radiation does not require a material medium and rate of energy transfer is affected by:

• Colour and texture of the surface
• Surface temperature
• Surface area

#### 9th Class Physics Chapter 9 Solved Numericals

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1. G SiDiQUE said:

Hello sir…
How can i download the whole guide in pdf for matric and fsc …

February 8, 2019

ISN’t the answer for WHAT HAPPENS TO THERMAL CONDUCTIVITY OF A WALL WHEN THICKNESS IS DOUBLED ” remains same ” because thermal conductivity is a constant

March 16, 2018
3. awais said:

what happens to thermal conductivity of a wall if its thickness is doubled?

March 26, 2017
4. abdullah said:

plzzzzzzzzzzzzzzzzzzzz upload the numericalz of unit 6,7&8
plzzz

July 11, 2014
5. UMMAMA said:

SIR I LIKE UR ANSWER.THANK U SSSSSSSSSSSSSOOOOOOOOOOOOOOOOOO MUCH

July 2, 2014
6. abdullah said:

June 10, 2014
7. Aminah said:

How can the thermal conductivity of a susbtance change by change in length? Doesn’t it have a fixed value for e.g thermal conductivity of air is always 0.026?

March 10, 2014
8. muskan said:

plzzzzzzzzzz upload numericals chap 6,7 and 8,all numericals of chap 9 plzzzzzzzzzzzz………..

February 9, 2014
• Suraj Kumar said:

9 chapter

September 13, 2017
9. sheroz said:

November 16, 2013

plzz 2 chap ke problems shrt question answers de den

October 27, 2013
11. qasim said:

pls help me also for ch 6,7and 8.
I and also thousands of students are looking toward you.
Pls respond .Thanx

September 29, 2013
• Raees said:

6 chapter is easy

March 11, 2014
12. qasim said:

pls help me also for ch 6,7% 8.
I % also thousands of students are looking toward you.
Pls respond .Thanx

September 29, 2013