Question

A 20 volt AC is applied to a circuit consisting of a resistance and a coil with negligible resistance. If the voltage across the resistance is 12 volt, the voltage across the coil is ______.

पर्याय

• 16 V

• 10 V

• 8 V

• 6 V

Answer 1

A 20 volt AC is applied to a circuit consisting of a resistance and a coil with negligible resistance. If the voltage across the resistance is 12 volt, the voltage across the coil is 16 V.

Explanation:

V_R = Effective Voltage across R

∴ V_R = I_eff R

V_L = Effective Voltage across L

`"V"_"L" = "I"_"eff" xx "L"`

Net V = `sqrt("V"_("R"^2) + "V"_("L"^2))`

`= sqrt("I"_("eff"^2) "R"^2 + "I"_("eff"^2) xx "L"^2)`

`20 = sqrt((12)^2 + "V"_("L"^2))`

`(20)^2 = (12)^2 + "V"_"L"^2`

400 = 144 + `"V"_"L"^2`

`"V"_"L" = sqrt(400 - 144) = sqrt256` = 16 Volts