Anand EduTech

 ***ELECTROMAGNETIC SPECTRUM:- The  orderly arrangement of electromagnetic wave in increase or decrease order of wavelength or frequency is called electromagnetic spectrum. *** RADIATION   :-- If the body temperature is more than 0K, the body transfers heat energy in the form of electromagnetic wave, this mode of heat transfer is called radiation. :--The mode of heat transfer by radiation does not require a medium. :- Electromagnetic waves can have different wavelength and can travel in vacuum with the same speed of light that is equal to   3× 10⁸ ms⁻¹. :-heat energy is carried by infrared waves with wavelength greater than 750nm. ***Newton Law Of Cooling:-- The rate of loss of heat of the body is directly proportional to the difference of temperature of the body. Q₁  A pan filled with hot food cool from 90°C to 86 °C in 120 seconds when the room temperature is at 20°C . how long will it lakes to cool from 71°C to 69°C?  Ans :- 42 seconds   ...

            There are three types modes of heat transfer. (1)  Conduction (2)  Convention (3) Radiation *** Conduction  :--    Conduction is a method of heat transfer in which the molecules of a substance transfer heat by vibrating without changes its position .                              or Conduction is a mode of transfer of heat between two adjacent part of body because of their temperature difference.           Length of the rod =L         Temperature difference(Δ T)= (T₁  - T₂) **Heat current(H) :-    Rate of flow of energy from hotter end to       colder end  is called heat current.                    [ H =  d Q/dt] :- S I unit of heat current is  j/s = watt(W). :- Dimensional formula of current is [ML²T⁻³] :...

 When heat is given or released to a matter, its temperature increases or decreases.                                     or In other words, it can be said that on heating a matter, the bonds between the molecules present in it get weakened And the matters are in their maximum expansion. now if you heat the matters, it will not change its temperature, but it changes its state of phase  that means  solid to liquid and liquid to gas.The reverse process is achieved when heat is released.                        In above explanation we found These state can be changed into one another by heating or cooling. this process of conversion of one stare of a matter into another state , is known as change of state.   ***LATENT HEAT(L) The amount of heat required to change the state of  one gram mass of a matter at constant tempe...

                        Calorimetry   Heat is a form of energy that is transferred from one body to another due to temperature difference.            calorie + metry             Heat  +  Measurement            It means measurement of heat . ***What is heat ? Heat is a type of energy and work is also a type of energy, so what is the difference between heat and work? Both heat and work are the modes of energy transfer in which one is the mechanical mode of energy transfer and the other is the nonmechanical mode of energy transfer. **HEAT :- Heat is a form of energy that is transferred from one body to another due to temperature difference. :-  It is a scalar quantity. :- It may  be  - ve , +ve and zero . :- S I unit of  heat is joule(J). :- C G S unit of heat is erg . :-  1 Joule =  10⁷ erg. :- Di...

                  QUESTION ANSWER (1) A wall clock that gives the correct time at 25°C  If that wall clock is kept at 55°C then how much time will it gain or lose ( coefficient of linear thermal expansion of the pendulum is 1.2 ×10⁻⁵/°C. (2) A second's pendulum of wall clock has a steel  wire . the clock is placed at 20°C , How much time does the clock loss or gain  in one month when the temperature is increased to  40°C ?  ( α = 1.2 × 10⁻⁵/°C )

(1)  BIMETALLIC STRIP :- If two strips of different materials placed one over another and rigidly joint is called bimetallic strip. :- If a bimetallic strip is heated then it bends such that the strip  of  material having high value of coefficient of linear thermal expansion will be on convex side. α of brass rod > α of steel rod (2)  Time period of pendulum       Thred length of pendulum = l Acceleration due to gravity = g T   =   2π    (l/g) Log T = Log (2π) + Log(l) - Log (g)                            Take both side Differentiation (1) A wall clock that gives the correct time at 25°C  If that wall clock is kept at 55°C then how much time will it gain or lose in one day ? (coefficient of linear thermal expansion of the pendulum is 1.2 ×10⁻⁵/°C) (2) A second's pendulum of wall clock has a steel  wire . the clock is placed at 20°C , Ho...

In case of thermal expansion of water (Liquid)  , water and vessel  both are expand simultaneously so both are explained One by One.                           Or  When a liquid in a vessel is heated then the observed expansion of the liquid is slightly less than its real expansion because along with the liquid the vessel also expands. Accordingly here we shall have two types of coefficients namely coefficient of apparent expansion and coefficient of real expansion.

 If a matter is heated(Temperature increase), the energy of the atoms present in it increases as well as the average distance between two atoms increases.The result due to which matter expands is called thermal expansion. ***There are three types of thermal expansion for solid. (1) Linear thermal expansion (2) Superficial thermal expansion (3) Volume thermal expansion.                                                                 In this expansion matter expand without change in its states. (1) Linear thermal expansion                Question (1). The length of a iron rod is 100cm at 15°C. When its temperature is raised to 115°C , then its length becomes 100.25cm . Calculate he coefficient of linear thermal expansion. (2) Calculate the change in length of steel rod  of leng...