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SSS TWO PHYSICS FIRST TERM HEAT ENERGY SCHEME OF WORK • • • • • • • • • • • • • • 1. MEASUREMENT OF HEAT ENERGY i) Heat Capacity ii) Specific Heat Capacity iii) Determination of Specific Heat Capacities in Solids and Liquids. 2. LATENT HEAT i) Concept of Latent Heat ii) Melting Point and Boiling Point iii) Specific Latent Heat of Fusion and Vaporization. iv) Dew Point and Relative Humidity 3. THE GAS LAWS i) Boyle’s Law ii) Charles’ Law iii) Pressure Law iv) General Gas Law SCHEME OF WORK • • • • • • • • • • • • • . • • • • 4. PRODUCTION AND PROPAGATION OF WAVES i) Pulsating System ii) Mechanical Waves iii) Energy Transmitted With Definite Speed, Frequency and Wavelength iv) Wave-Form v) Mathematical Relationship vi) Types of Waves 5. PROPERTIES OF WAVES i) Reflection ii) Refraction iii) Diffraction iv) Interference v) Polarization 6.CONCEPT OF LIGHT WAVES i) Source of Light ii) Propagation of Light iii) Transmit ion of Light iv) Sun’s Energy and The Radiation to The Earth SCHEME OF WORK • • • • • • • • • • 7. REFLECTION OF LIGHT AT PLANE SURFACES i) Laws of Reflection ii) Formation of Images iii) Rotation of Mirrors iv) Applications of Mirror. 8. REFLECTION OF LIGHT AT CURVED SURFACES i) Concave and Convex Mirrors ii) Images Formation on Curved Mirror iii) Mirror’s Formula iv) Experimental Determination of Focal Length DEFINITION OF TERMS Heat capacity is the quantity of heat required to change/raise/lower the temperature of a body by 1K. The unit is Joule per Kelvin. Specific heat capacity is the quantity of heat required to raise the temperature of a unit mass of a substance through unit temperature. The unit is Joule per Kilogram Kelvin. The formula is Q = mcϴ In calorimetry and method of mixture Heat lost by substance = heat gained by substance mcϴ = mcϴ Specific latent of fusion is the quantity of heat required to convert a unit mass of a substance from solid to liquid without change in temperature. Mathematically expressed as Q = mL When electrical means of heating is involved, the formula becomes Ivt = mcϴ Ivt = mL Where L is the constant of proportionality called the specific latent heat of fusion or vaporization measured in Joules per kilogram. Definition of terms Vapour pressure is the pressure exerted by the molecules of a vapour. Saturated vapour is a vapour that is in contact with its own liquid within a confirmed space. Saturated vapour pressure(SVP) is the pressure exerted by the saturated vapour. Dew point is the temperature at which the water vapour present in the air is just sufficient to saturate. Assignment • A block of lead of mass 100kg in a crucible and at a temperature of 40 degree Celsius was placed in an electric furnace rated 10kw. If the melting point of lead is 320 degree Celsius, calculate the (i) quantity of heat required to heat the lead to its melting point. (ii) additional heat energy required to melt the lead. (iii) time taken to supply this additional energy specific heat capacity of lead = 120J/kgk, specific latent heat of fusion of lead = 25000J/kg.