This set of Network Theory test focuses on “Maximum Power Transfer Theorem”.

1. The condition for maximum voltage to be transferred to the load is?

a) Source resistance greater than load resistance

b) Source resistance less than load resistance

c) Source resistance equal to load resistance

d) Source resistance greater than or equal to load resistance

View Answer

Explanation: Our aim is to find the necessary conditions so that the power delivered by the source to the load is maximum. The condition for maximum voltage to be transferred to the load is source resistance less than load resistance.

2. The condition for maximum current to be transferred to the load is?

a) Source resistance greater than or equal to load resistance

b) Source resistance equal to load resistance

c) Source resistance less than load resistance

d) Source resistance greater than load resistance

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Explanation: The condition for maximum current to be transferred to the load is source resistance greater than load resistance. For many applications an important consideration is the maximum power transfer to the load.

3. The condition for maximum power to be transferred to the load is?

a) Source resistance equal to load resistance

b) Source resistance greater than load resistance

c) Source resistance greater than or equal to load resistance

d) Source resistance less than load resistance

View Answer

Explanation: The condition for maximum power to be transferred to the load is source resistance equal to load resistance. Maximum power transfer is desirable from the output amplifier to the speaker of an audio sound system.

4. In the circuit shown determine the value of load resistance when the load resistance draws maximum power?

a) 50

b) 25

c) 75

d) 100

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Explanation: The source delivers maximum power when load resistance is equal to source resistance. So, load resistance = 25Ω.

5. Find the value of the maximum power in the circuit shown in the question 4.

a) 25

b) 50

c) 75

d) 100

View Answer

Explanation: Current = 50/(25+25)=1A. Maximum power delivered to load = (I)

^{2}×R

_{L}. On substituting the values obtained and given we get maximum power in the circuit is (1)

^{2}×25=25W.

6. If the source Z_{S} is complex, then the condition for the maximum power to be transferred is?

a) Z_{L}=Z_{S}

b) Z_{L}=Z_{S}*

c) Z_{L}=-Z_{S}

d) Z_{L}=-Z_{S}*

View Answer

Explanation: If the source Zs is complex, then the condition for the maximum power to be transferred is Z

_{L}=Z

_{S}* that is load impedance is complex conjugate of source impedance.

7. If Z_{S}=R_{S}+jX_{S}, Z_{L}=R_{L}, then condition for maximum power to be transferred is?

a) R_{L}=|Z_{S}|

b) R_{L}=Z_{S}

c) R_{L}=-|Z_{S}|

d) R_{L}=-Z_{S}

View Answer

Explanation: If Z

_{S}=R

_{S}+jX

_{S}, Z

_{L}=R

_{L}, then condition for maximum power to be transferred is R

_{L}=|Z

_{S}| that is maximum power is transferred when the load resistance is equal to the magnitude of the source impedance.

8. Find the load resistance so that the load draws maximum power.

a) 6

b) 7

c) 8

d) 9

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Explanation: The condition for the load to draw maximum power is by open circuiting terminals a and b and the load resistance is R=(10×6)/(10+6)+(15×8)/(15+8)=8.96Ω≅9Ω.

9. Find the maximum power (mW) that is delivered by the source in the circuit shown in the question 8.

a) 50

b) 51

c) 52

d) 53

View Answer

Explanation: V

_{a}=50×6/(10+6)=18.75V, V

_{b}=50×8/(15+8)=17.39V. V

_{ab}= V

_{a}– V

_{b}= 18.75 – 17.39 = 1.36V. I=1.36/(9+9)=75mA. P=I

^{2}R=(0.075)

^{2}×9=0.051W ≅51mW.

10. If Z_{S}= R_{S}+jX_{S}, Z_{L}=R_{L}+jX_{L}, then if R_{L} is fixed, the condition for maximum power to be transferred is?

a) X_{S}=X_{L}

b) X_{S}=-X_{L}

c) X_{S}+X_{L}=0

d) None of the above

View Answer

Explanation: If Z

_{S}= R

_{S}+jX

_{S}, Z

_{L}=R

_{L}+jX

_{L}, then if R

_{L}is fixed, the condition for maximum power to be transferred is X

_{S}=-X

_{L}.

**Sanfoundry Global Education & Learning Series – Network Theory.**

To practice all areas of Network Theory for tests, __here is complete set of 1000+ Multiple Choice Questions and Answers__.