Physics Ch 8 Class 9
Important Easy Notes of Physics Ch 8 Class 9 English Medium written by Professor Mr. Samiullah Suib. These notes are very helpful in the preparation of Physics for students of the 9th class Physics English Medium and these are according to the paper patterns of all KPK Book Boards.
Summary and Contents:
Topics which are discussed in the notes are given below:
- Definition of Temperature: symbol, unit, other units, quantity, nature and Measurement.
- Definition of Heat: symbol, unit, other units, quantity, nature and Measurement.
- Differentiate between Temperature and Heat.
- Definition of Internal Energy: symbol, unit, other units, quantity, nature and Measurement.
- Write factors of internal energy
- Definition of thermometry
- Definition of thermometer
- Definition of thermometric property with examples
- Definition of temperature scales and types of temperature scales.
- Write history and other name also explanation of centigrade scale
- Write history and other name also explanation of Fahrenheit scale
- Write history and other name also explanation of Kelvin scale
- Write definition and other name of Kelvin Zero.
- Relation between different scale of temperature.
- Definition of thermal expansion: Cause, Explanation and write its factor.
- Definition of thermal expansion of solids also explain it.
- Definition of coefficient of linear thermal expansion: Symbol, Mathematical Form, Unit and Factor.
- Definition of volume thermal expansion also explain it.
- Definition of thermal expansion of liquids also explain it.
- Types of thermal expansion of liquids.
- Definition of real expansion of liquid and also write its symbol.
- Definition of Apparent expansion of liquid and also write its symbol.
- Definition of Anomalous expansion of water also explain it.
- Question: Why ice floats on water?
- Application and consequences of thermal expansion.
- Definition of Heat Capacity: Symbol, mathematical form, factor, unit.
- Definition of specific heat capacity with notation.
- Definition of Latent Heat of Fusion.
- Definition of specific latent heat of fusion.
- Definition of latent heat of vaporization.
- Definition of specific latent heat of vaporization also write its mathematical form.
- Definition of vaporization of liquids with examples.
- Differentiate between evaporation and boiling point.
- Applications of cooling by evaporation.
- Ordinary electric fan increases the kinetic energy of the air molecules caused by the fan blades pushing them means the air temperature increases slightly rather than cool the air? Why use it.
- Why are the small gaps left behind the girders mounted in the walls?
- Why you should not put a closed glass jar into a campfire. What could happen if you tossed an Empty glass jar, with the led on tight into a fire?
- Explain why it is advisable to add water to an overheated automobile engine only slowly, and only with the engine running.
- Burns caused by steam at 100^o C on the skin are often more severe than burns caused by water at 100^o C.
- Explain why cities like Karachi saturated by the ocean tend to have less extreme temperature than inland cities at the same latitude.
- An iron rim which is fixed around a wooden wheel is heated before its fixture. Explain it.
- Why we feel cool after perspiration?
- Solved Numerical of the exercise Physics Ch 8 Class 9.
- Perform the temperature conversion (a)Temperature difference in the body. The surface temperature of the body is normally about 7 °C lower than the internal temperature. Express this temperature difference kelvins and in Fahrenheit degrees. (b) Blood storage. Blood stored at 4.0 °C lasts safely for about three weeks, whereas blood stored at -160 °C lasts for 5 years. Express both temperatures on the Fahrenheit and Kelvin scales.
- Consider a meter-stick composed of platinum (the coefficient of linear expansion for platinum is a = 8.8×10° K¯¹). By what amount does the length of this meter-stick change if the temperature increases by 1.0K.
- A railway line made of iron is 1200km long and is laid at 25 °C. By how much will it contract in winter when the temperature falls to 15 °C? By how much will it expand when the temperature rises to 40°C in summer? (The coefficient of linear expansion for iron is a =12×106 K¯¹).
- The volume of a brass ball is 800 cm³ at 20°C. Find out the new volume of the ball if the temperature is raised to 52°C. The coefficient of volumetric expansion of brass is 57×10^-6 к¹.
- What is the specific heat of metal substance if 135kJ of heat is needed to raise 4.1 kg of the metal from 18.0°C to 37.2°C?
- How much heat is needed to melt 23.50 kg of silver that is initially at 25°C? (Specific heat of silver is c=230JkgK¹ Latent heat of fusion for silver is L₁ = 8.8×10^4).