# Electronics - Transformers

Exercise : Transformers - General Questions
1.
When does maximum power transfer happen from the source to the load?
When the source resistance is greater than the load resistance
When the source resistance is less than the load resistance
When there is negligible source resistance
When the source resistance equals the load resistance
Explanation:
No answer description is available. Let's discuss.

2.
A transformer is plugged into a 120 V rms source and has a primary current of 300 mA rms. The secondary is providing 18 V across a 10 load. What is the efficiency of the transformer?
88%
90%
92%
95%
Explanation:
No answer description is available. Let's discuss.

3.
The coefficient of coupling between two coils is 0.45. The first coil has an inductance of 75 mH and the second coil has an inductance of 105 mH. What is the mutual inductance between the coils?
3.54 mH
7.88 mH
39.9 mH
189.3 mH
Explanation:
No answer description is available. Let's discuss.

4.
Increasing the number of turns of wire on the secondary of a transformer will
increase the secondary current
decrease the secondary current
have no effect on the secondary current
increase the primary current