Question

An A.C. voltage source of variable angular frequency `omega` and fixed amplitude V connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When `omega` is increased, ______.

Options

• the bulb glows dimmer.

• the bulb glows brighter

• total impedence of the circuit is unchanged.

• total impedence of the circuit increases.

Answer 1

An A.C. voltage source of variable angular frequency `omega` and fixed amplitude V connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When `omega` is increased, the bulb glows brighter.

Explanation:

`"I"_"rms" = "V"_"rms"/sqrt( "R"^2 + 1/(omega^2"C"^2))`

`therefore` As ro increases, `"I"_"rms"` increases and hence the bulb glows brighter.