Question

Give answer for the following :-
1 explain joule's law of heating with derivation
2. Achievement and drawbacks of Mendeleev periodic table any three
3. Newlands law of octaves and its limitations any three

Answer 1

H = power × time
H = W/T × T
H = VQ/T × T
H = IR×IT/T ×T
H= I²RT

achievements:
1. if new inert gases were to be discovered, they could be adjusted in the table without interrupting with the rest of the table
2. he left space for the elements which were not discovered yet and even guessed their properties

drawbacks:
1. he placed two different elements in the same slot.
2. no specific place was given to hydrogen.
3. he plays the some elements with more mass before the elements with less mass
4. he could not explain the placement of isobars.

according to the newlands law of octaves every 8th element in the series repeats the properties of the first element like the octaves in music.
limitations:
1. he could only place elements till calcium.
2. he thought that there were only 56 elements in the nature.
3. he placed 2 elements with different properties in the same slot

Answer 2

1. Heat = Power * Time 
Power = Work / Time ............. 1
From 1
Heat = Work / Time *Time
Work = VQ...............2
From 2
Heat=V (It)
Now you can find more equations by putting values of v and i

2.Mendeleev periodic table
a.According to him physical and chemical properties of atom depends on their atomic mass 
b.He had classified many atoms in his table .
c.He make easy to form oxide and hydrogen of any atom
Limitation :
a.According to him physical and chemical properties of atom depends on their atomic mass  but in real it depend on their atomic number
b.He had arranged atoms having different physical and chemical properties in same group
c.He had arranged atoms having same physical and chemical properties in different group 
d.He cannot find the place of hydrogen

3. Newland law of octave 
According to him the physical and chemical properties of first atom is same to the eight atom .

Limitations :
a.This didnot work after calcium 
b.He cannot find the place of hydrogen
c.He also arranged two or more atoms in one class