1) 13.8 V
We can use the transformer equation:
[tex]\frac{N_p}{N_s}=\frac{V_p}{V_s}[/tex]
where we have
[tex]N_p = 300[/tex] is the number of turns in the primary coil
[tex]N_s=18[/tex] is the number of turns in the secondary coil
[tex]V_p=230.0 V[/tex] is the voltage in the primary coil
[tex]V_s = ?[/tex] is the voltage in the secondary coil
Solving for Vs, we find
[tex]V_s = \frac{N_s}{N_p}V_p=\frac{18}{300}(230.0 V)=13.8 V[/tex]
2) 5.17 A
For an ideal transformer, the power in input is equal to the power in output, so we can write:
[tex]P_{in} = P_{out}\\V_p I_p = V_s I_s[/tex]
where
[tex]V_p=230.0 V[/tex] is the voltage in the primary coil
[tex]V_s = 13.8 V[/tex] is the voltage in the secondary coil
[tex]I_p=0.31 A[/tex] is the current in the primary coil
[tex]I_s = ?[/tex] is the current in the secondary coil
Solving for Is, we find
[tex]I_s = \frac{I_p V_p}{V_s}=\frac{(0.31 A)(230.0 V)}{13.8 V}=5.17 A[/tex]
