I was doing a question on transformers and found this really confusing question:
A 100% efficient transformer converts a 240V input voltage to a 12V output voltage. The output power of the transformer can be a maximum of 20W. The output is connected to two 0.30A bulbs in parallel. One of the bulbs fails. How does the current in the primary coil change?
What I did:
Since I have been given power and voltage I thought it would be helpful to figure out the current, so I did that which was fairly easy
20W/12V = 1.67 A
the output is connected to 2 0.3A bulbs so if one fails that's only 1 0.3A bulb
What I am stuck on
Now, this is where I kinda fall apart since I don't know where to go, I thought I would need to figure out some sort of ratio due to the transformer rule of the ratio of coil turns is equal to the ratio of voltages, but I don't really see where I would get information of the number of coils turns, however, my intuition is telling me that the current would increase...
Am I missing something that I haven't calculated from the question?