A lamp is connected to the secondary part of an ideal transformer. What will happen to the brightness of the lamp if the number of turns in secondary coil is increased?
Vs / Vp = Ns / Np = Ip / Is
P = V.I = I2R = V2/R
The Attempt at a Solution
I have three different cases:
a. Because this is an ideal transformer, the power at primary will be the same as at secondary so the power delivered to the lamp will stay constant and the brightness will stay the same
b. If the number of turns in secondary coil is increased, the voltage at secondary will also increase. It means, the power delivered to the lamp will also increase (P = V2 / R) and the brightness will increase
c. If the number of turns in secondary coil is increased, the current at secondary will decrease. It means, the power delivered to the lamp will also decrease (P = I2 R) and the brightness will decrease
Which one is correct? And what factors affect the brightness of a lamp? Is it voltage only, or current only, or power only, or combination of them?