A light bulb is connected to a 120.0-V wall socket. The current in the bulb depends on the time t according to the relation I = (0.737 A) sin [(303 rad/s)t]. (a) What is the frequency of the alternating current? (b) Determine the resistance of the bulb's filament. (c) What is the average power delivered to the light bulb?

Respuesta :

Answer:

Explanation:

Given

Voltage [tex]V=120\ V[/tex]

Current [tex]I=0.737\sin [303t][/tex]

frequency of the alternating current is given by

[tex]f=\frac{\omega }{2\pi }v[/tex]

[tex]f=\frac{303}{2\pi }[/tex]

[tex]f=48.21\ Hz[/tex]

(b)Mean current [tex]I_m=0.737\ A[/tex]

[tex]I_{rms}=\frac{I_m}{\sqrt{2}}[/tex]

[tex]I_{rms}=\frac{0.737}{\sqrt{2}}[/tex]

[tex]I_{rms}=0.521\ A[/tex]

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

[tex]R=\frac{120}{0.521}[/tex]

[tex]R=230.2\ \Omega [/tex]

(c)Average Power

[tex]P=V_{rms}I_{rms}[/tex]

[tex]P=62.52\ W[/tex]

Answer:

a) [tex]f=48.2239\ Hz[/tex] is the frequency of the AC.

b) [tex]R=230.265\ \Omega\\[/tex]

c) [tex]P=62.532\ W[/tex]

Explanation:

Given:

  • voltage rating of the bulb, [tex]V_{rms}=120\ V[/tex]
  • current in the bulb as the function of time, [tex]I=0.737A.\sin(303t)[/tex]

Comparing the expression of the current with the standard form we have:

a)

Angular frequency,

[tex]\omega=303\ rad.s^{-1}[/tex]

[tex]2\pi.f=303[/tex]

[tex]f=48.2239\ Hz[/tex] is the frequency of the AC.

b)

From the expression of current we have the maximum value of current as:

[tex]I_m=0.737\ A[/tex]

Now the RMS current is:

[tex]I_{rms}=\frac{I_m}{\sqrt{2} }[/tex]

[tex]I_{rms}=\frac{0.737}{\sqrt{2} }[/tex]

[tex]I_{rms}=0.5211\ A[/tex]

So, resistance

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

[tex]R=\frac{120}{0.5211}[/tex]

[tex]R=230.265\ \Omega\\[/tex]

c)

We know that average power is given as:

[tex]P=V_{rms}.I_{rms}[/tex]

[tex]P=120\times 0.5211[/tex]

[tex]P=62.532\ W[/tex]

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