## HEAT

There are mainly 4 scales of temperature :-
1. Kelvin(K)
3. Fahrenhiet(*F)
4. Reaumur(*r)

The relation between the following scales of temperature is as follows :

*C -32 = K-273 = *F-32 = *r
5           5              9        4

Heat energy is denoted by ‘Q’
Work is directly proportional to energy
So , W=JQ ( Here , J is the convergent factor whose value is equal to 4.18J/cal )
So we can also say that 1 cal = 4.18J

To test your understanding , here’s a small question :-
1. If the amount of work done by a body is 20.9J , find the amount of heat energy produced
By formula ,
W=JQ
20.9 = 4.18 * Q
Q = 20.9/4.19
Q=5 calories

See , it’s that simple ! Now let’s move on

### THE CONCEPT OF SPECIFIC HEAT

Specific heat is denoted by ‘C’
Heat energy is directly proportional to the mass of the object -1
Heat energy is directly proportional to the temperature difference – 2
By 1 and 2 ,
Q = m.C.dtheta

Where m – Mass
C – specific heat ( constant )
dtheta – delta theta ( this denotes the temperature difference )

Magnitude of C of water – 1
Magnitude of C of ice – ½

### LATENT HEAT

As you all must be aware , latent heat is the amount of heat energy which is required by a particle to change it’s physical state
Q = m.L
Where Q=Heat energy
m = mass of the object
L = Latent heat

L of ice ---- 80 cal(By default)

The Challenger Question :-
Science is nothing without application , and if you’re not able to apply what you’ve just learnt , then there’s absolutely no point in learning

Here’s a question for you , it isn’t that tough if you use your common sense

QUESTION :-
Container A :- 100g Water at 100*C
Container B :- 100g Ice at -50*C

If the water kept in Container A is poured into Container B , calculate the amount of ice which will melt as a result of this

I can sense that you’re a bit baffled , so here’s the solution , now try to understand

Heat energy of water = m.C.dtheta
= 100 * 1 * 100
= 10000 calories
Total heat energy of ice = m.c.dtheta + m.L
= 100 * ½ * 50 + 100*80
= 2500 cal + 8000 cal

Now what we have to see is , this latent heat ( 8000 cal ) will be responsible for melting the ice
But , this 2500 cal of heat energy will be responsible for bringing the temp. of ice to 0*C ( it’s quite obvious )
Only after the temperature reaches 0*C , the ice will start to melt
Therefore , heat energy of water which will melt the ice   = total heat energy of water – heat energy required to lower the temperature of ice
= 10000 – 2500
= 7500g

So , % of ice melted = 7500/8000 * 100
= 93.8%
This translates to 93.8g

FINAL ANSWER :- 93.8g of ice will melt

You must surely be happy today , because you’ve learnt something new

Stay tuned for more scientific information
I hope you liked today’s topic
• Aryan Awasthi
Enjoy your high school with - High School Pedia : www.highschoolpedia.com

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