VI - From the ACGHA loop
Potential difference at battery = - V1
Potential difference at resistancess = + I1
R1 + (I1
+ I2
) x R3
The resultaint Potential difference in the loop is = - V1
+ I
1
R1 + (I1
+ I2
) x R3 = 0
Example 5 : Find the resultaint potential diffrence from the given
figure based on Loops law.
Solution: Shown in
For the loop ACDBA,
-V2
+ I2
R2
– I1
R1
+V1
= 0
For the loop EFDCE
-(I1
+I2
) R3
– I2
R2
+ V2
= 0
For the loop EFBAE
-(Ic1
+I2
) R
3
– I1
R1
+V1
= 0
Example 6: Find electric current drawn(fig-30)from the battery of
emf 12V.
Solution: Let I = I1
+I2
be the current drawn from
emf 12V.
From the figure E. Using the loop law,
For the loop DABCD,
-3 (I1
+I2
) + 12 – 5 – 2I1
= 0 ……….. (a)
For the loop DAFED,
-3 (I1
+I2
) + 12 – 4I2
= 0 ………. (b)
Solving the equation (a) & (b)
We get I1
= 0.5 A and I2
= 1.5 A
Total current drawn is then I = 0.5 + 1.5 = 2A
• You might have heard the sentences like “this
month we have consumed 100 units of current”. What does ‘unit’
mean?
• A bulb is marked 60W and 120V. What do these values indicate?
Let us see.
Electric power
The electric appliances that we use in our daily life like heater,
cooker, fan, and refrigerator etc. consume electric energy.
Let us consider
a conductor of resistance ‘R’ through which
an electric current ‘I’ passes.
We know that
when current passes through conductor,
heat energy is generated.
Consider that a charge Q Coulomb
passes through a point A, moves to point B