A step-up transformer has 120 turns on its primary coil. It has 1150 turns on its secondary coil. The primary circuit is supplied with an alternating current at 120 V.

The current in the secondary circuit is 2.4 A. What current is in the primary circuit?

formula??

induced emf in secondary= (number of turns in secondary/ number of turns in promary)* applied emf in primary.

this can be changes to solve for applied emf in primary instead.

To determine the current in the primary circuit of a step-up transformer, you can use the formula:

I1 / I2 = N2 / N1

Where:
I1 is the current in the primary circuit
I2 is the current in the secondary circuit
N1 is the number of turns on the primary coil
N2 is the number of turns on the secondary coil

In this case, you have the following values:
N1 = 120 turns (primary)
N2 = 1150 turns (secondary)
I2 = 2.4 A (secondary)

Plugging these values into the formula, we can solve for I1:

I1 / 2.4 A = 1150 turns / 120 turns

To simplify the equation, we can cancel out the turns:

I1 / 2.4 A = 1150 / 120

Now we can cross-multiply and solve for I1:

I1 = (2.4 A * 1150 turns) / 120 turns

I1 = 23 A

Therefore, the current in the primary circuit is 23 A.