00:01
Hello students, in this question for the given circuit we have to find the value of r for maximum power absorbed and we have to find the maximum power absorbed by r.
00:32
To find the value of r we have to find the thevenin equivalent circuit for the terminals of resistor r and then we can find the maximum power transferred using the formula p is equal to thevenin voltage squared divided by 4 times thevenin resistance.
00:59
Let us consider this equation 1.
01:04
Now we have to find the thevenin resistance.
01:07
For finding the thevenin resistance we can use the following circuit.
01:51
In this circuit the independent voltage source has been shorted as well as the resistance r.
02:20
So the equivalent resistance of the circuit r will be equal to r equivalent.
02:36
This will be equal to the thevenin resistance which is equal to 20 parallel 80 plus 90 parallel 10.
02:48
Substituting the values we get 20 into 80 divided by 20 plus 80 plus 90 into 10 divided by 90 plus 10.
03:06
So the resistance r will be equal to thevenin resistance.
03:10
This will be equal to 25 ohms...