Heat Equation and Specific Heat Capacity
Heat equation:
Let us consider a body having mass 'm' is heated so that its temperature changes from t_{1} to t_{2}. Therefore, change in temperature is t_{2}  t_{1}. The amount of heat "Q" depends on two factors i.e. mass of the body and temperature differences
I.e. Q∝m ........(i)
Q∝( t_{2}  t_{1})
Q∝dt ............ (ii) Where dt is temperature difference
Combining equation (i) and (ii)
Q∝mdt
Q = smdt
Therefore, Q = msdt
Where, 's' is proportionality constant and is known as specific heat capacity.
Specific Heat capacity:
we have,
Q = msdt
or, s = \(\frac{Q}{mdt}\)
When,
m = 1 kg
dt = 1 degree Celsius
s = Q
Thus, Specific heat capacity is defined as the amount of heat required to change the temperature of 1 kg of substances through 1°C or 1k
Unit of specific heat capacity:
We have,
S =\(\frac{Q}{mdt}\)
SI unit of heat energy (Q) is joule
SI of unit of mass (m) is kilogram
SI unit of change in temperature (dt) is Kelvin
Therefore, S =\(\frac{J}{kgK}\)=Jkg^{1}K^{1}
Note: Different substances have different specific heat capacity. The substance that has more specific heat capacity changes its temperature slowly (when it is heated its temperature rise up slowly and when it is cooled its temperature fall down slowly). The substances that have less specific heat capacity changes its temperature fast (when it is heated its temperature rise up quickly)
Specific heat capacity of some materials:
Materials  Specific heat capacity 
Gold  134 Jkg^{1}K^{1} 
Mercury  138 Jkg^{1}K^{1} 
Sand  800 Jkg^{1}K^{1} 
Ice  2100 Jkg^{1}K^{1} 
water  4200 Jkg^{1}K^{1} 
Thermal capacity:
Thermal capacity is defined as the amount of heat required to change the temperature of thesubstance through 1 degree Celsius. It is denoted by "C".
Mathematically,
C = m s where,
C = thermal capacity
M = mass of substance
S = specific heat capacity.
Its SI unit is J/K or J/°C
Principal of calorimetry:
It states that "The amount of heat lost by the hotter body is equal to the amount of heat gained by the colder body, avoiding external loss of heat."
Let us consider two bodies A and B where masses are m_{1} and m_{2}. Let, t_{1} and t_{2} be the initial temperature of A and B respectively. Let specific heat capacity of A and B be S_{1} and S_{2} respectively. If A is hotter body and B is the older body when they are kept in thermal contact, A will lose heat and B will gain heat until their temperature becomes equal "t".
Now,
Amount of heat gained by B (Q_{2}) = m_{2}S_{2}(t  t_{2})
Amount of heat lost by A (Q_{1}) = m_{1}S_{1}(t_{1}t)
According to principle of calorimetry amount of heat loosed by A is equal to amount of heat gained by B
Therefore, m_{1} S_{1}(t_{1}t) = m_{2} S_{2} (tt_{2})
 Heat equation is Q = msdt where, S is proportionality constant and is known as specific heat capacity.
 Specific heat capacity is defined as the amount of heat required to change the temperature of 1 kg of substances through 1°C or 1k.
 The substance that has more specific heat capacity changes its temperature slowly (when it is heated its temperature rise up slowly and when it is cooled its temperature fall down slowly).
 The degree of hotness and coldness of a substance is called temperature.
 The intensity of molecular vibration of the substance is called its temperature.
Heat  Temperature 
It is the sum of kinetic energy possessed by the substance.  It is the intensity of kinetic energy of the molecules of the substance. 
Heat is the form of energy that gives us sensation of warmth.  The degree of hotness and coldness of a substance is called temperature. 
It is measured in Joules.  It is measured in degree Celsius. 
It is the cause.  It is an effect. 
The specific heat capacity of water is 4200 J/ Kg ^{0}C means that 4200 J heat energy is required to increase or decrease the temperature of 1 kg water by 1 ^{0}C.
Given,
Heat amount (Q) =1000J
Mass of iron (m) = 2 kg
Temperature decreased (t) = 90°C 15°C
= 75°C
Specific heat capacity (s)=?
We know,
Q = m × s ×t
or, s = \(\frac{Q}{mt}\)
= \(\frac{1000}{2× 75}\)
= 6.67J/kg°c
Specific heat capacity of a substance can be defined as the amount of heat required to raise the temperature of kg of the substance by 1°c.The specific heat of the substance is generally represented by letters.The unit of specific heat capacity is J/kg°c.
Given,
Mass of the iron (m) =150 gm =0.150kg.
Increase in temperature (t) = 150°c  25°c =125°c
The specific heat of the iron (s) = 480J/kg°c
Quantity of heat required (Q) = ?
We have from the relation
Q = m× s× t
= 0.150× 480× 125
= 9,000 Joules
Hence , 9000 Joules heat is required.

The amount of heat required to raise the temperature of 1 kg of substances through 1 degree C or 1k is ______.
specific heat capacity
heat capacity
thermal capacity
heat energy

The amount of heat lost by the hotter body is equal to the amount of heat gained by colder body, avoiding external loss of heat is ______.
thermal capacity
heat capacity
heat energy
principle of calorimetry

Heat equation is ______.
Q = mdt
Q = ms
Q = msdt
Q = sdt

Two blocks of zinc with different masses are at room temperature. Each block then absorbs the same amount of heat over 10 minutes. When the temperature of each block is then measured, block 1 is at a higher temperature than block 2. Which of the following statements most likely describes the zinc blocks?
The specific heat of block 1 is less than the specific heat of block 2.
The specific heat of block 1 is greater than the specific heat of block 2.
The mass of block 1 is less than the mass of block 2.
The mass of block 1 is greater than the mass of block 2.

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Vibek BhattaraiWell water is wamer in the mornibg during winter. Why? 
Jan 07, 2017 
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Manish ShresthaWhat is heat equation? 
Dec 29, 2016 
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When we get out of the bed on a very co;d morning,we feel the air of the same room cold but when we go out fore something and return back to same room we feel the same room warmer.why? 
Dec 29, 2016 
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