An A.C. voltage v=80sin120πt volts is applied across a 24.0 – Ω resistor. What will an ammeter connected in series with the resistor read?

Respuesta :

Given:

The voltage applied,

[tex]V=80\sin(120\pi t)[/tex]

The resistance of the resistor, R=24.0 Ω

To find:

The reading in the ammeter.

Explanation:

An ac ammeter connected in series with the resistor reads the root mean square value of the current, i.e., I_rms.

Comparing the given equation of the voltage to the standard equation,

[tex]V=V_0\sin(\omega t)[/tex]

We get, V₀=80 V

The root mean square value of the voltage is given by the equation,

[tex]V_{rms}=\frac{V_o}{\sqrt{2}}[/tex]

On substituting the known values,

[tex]\begin{gathered} V_{rms}=\frac{80}{\sqrt{2}} \\ =56.6\text{ V} \end{gathered}[/tex]

Thus the value of I_rms is calculated by the equation,

[tex]I_{rms}=\frac{V_{rms}}{R}[/tex]

On substituting the known values,

[tex]\begin{gathered} I_{rms}=\frac{56.7}{24.0} \\ =2.4\text{ A} \end{gathered}[/tex]

Final answer:

Thus the reading of the ac ammeter connected in series with the resistor is 2.4 A.