A Christmas light is made to flash via the discharge of a capacitor. The effective duration of the flash is 0.25 s (which you can assume is the time constant of the capacitor), during which it produces an average 55 mW from an average voltage of 3.1 V. 25% Part (a) How much energy, in joules, does it dissipate? E 25% Part (b) How much charge, coulombs, moves through the light? q= 1 25% Part (c) Find the capacitance of the light, in farads. C = 1 25% Part (d) What is the resistance, in ohms, of the light? R= |

Respuesta :

Answer:

The correct solution is:

(a) [tex]1.375\times 10^{-2} \ J[/tex]

(b) [tex]4.43\times 10^{-3} \ C[/tex]

(c) [tex]1.42\times 10^{-3} \ F[/tex]

(d) [tex]178.57 \ \Omega[/tex]

Explanation:

The given values are:

Effective duration of the flash,

ζ = 0.25 s

Average power,

[tex]P_{avg}=55 \ mW[/tex]

       [tex]=55\times 10^{-3} \ W[/tex]

Average voltage,

[tex]V_{avg}=3.1 \ V[/tex]

Now,

(a)

⇒ [tex]E=P_{avg}\times \zeta[/tex]

On substituting the values, we get

⇒     [tex]=55\times 10^{-3}\times 0.25[/tex]

⇒     [tex]=1.375\times 10^{-2} \ J[/tex]

(b)

⇒ [tex]E=Q\times V_{avg}[/tex]

then,

⇒ [tex]Q=\frac{E}{V_{avg}}[/tex]

On substituting the values, we get

⇒     [tex]=\frac{1.375\times 10^{-2}}{3.1}[/tex]

⇒     [tex]=4.43\times 10^{-3} \ C[/tex]

(c)

⇒ [tex]C=\frac{Q}{V}[/tex]

⇒     [tex]=\frac{4.43\times 10^{-3}}{3.1}[/tex]

⇒     [tex]=1.42\times 10^{-3} \ F[/tex]

(d)

As we know,

⇒ [tex]R=\frac{1}{4C}[/tex]

⇒     [tex]=\frac{1}{4\times 1.42\times 10^{-3}}[/tex]

⇒     [tex]=\frac{1000}{5.6}[/tex]

⇒     [tex]=178.57 \ \Omega[/tex]