Question

1. what will be the effective resistance in the parallel connection ....
solve it with formula
2. what are the characteristics of connecting the bulbs in parallel method?
3. why are the domestic appliances connected in parallel method?

Answer 1

Sometimes we dont have desire resitance for the circuit. Even if we go and find out in the market we dint get the one...In order to obtain desire Resitance we use the concept of combination of resistors...

By combining resistirs we can obtain desire resistance for the circuit...

Resistors can be combined in three ways :
1 ) Series
2) Parallel
3) Mixed ( Series + Parallel )

Suppose we have 2 ohm resistances available in the market , and our circuit need 1 ohm...To obtain 1 ohm resistance , we simply combined two resistors of 2 ohm each in parallel to get 1 ohm resistor as per following relation :

1 / Rp = 1/ R + 1 / R = 1/2 + 1/2 = 1
=> 1 / Rp = 1
=> Rp = 1 ohm...
When resitiors are connected in parallel , the resistance of the circuit ( net resistance ) always decreases...

For n resitors in parallel connection :
Effective resitance = Rp or Re
1 /Re = 1 / R1 + 1 / R2 + .... + 1 / Rn.

For two resistances
=================
1 / Re = 1 / R1 + 1 / R2
1 /Re = ( R1 + R2 ) / (R1 x R2)
Re = ( R1 x R2 ) / ( R1 + R2 )
Re = (Product of two) / (Sum of two)


Characteristics
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In parallel connection , voltage across each resistances( bulbs ) remain constant.
Current is different acrosss each bulb ( resistance )

Domestic appliances are connected in paralled due to following resons :
1 ) Each appliances get same amount of voltage to operate...
2) If one of the appliance stop working , it doesnt affect the working of other appliances which are connected in parrallel with the faulty appliance...