A sine wave voltage is applied across a capacitor. When the frequency of the voltage is decreased, what happens to the current?

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Answer 1 · 2015-06-23T07:44:26

If the frequency of voltage is decreased, then current value is also #color(blue)(decreased)#.

If the opposition to applied voltage is increased, then current value is decreased.

Here,the opposition is due to reactance of capacitor.

#X_c=1/(2pifC)#

#X_c#=reactance of capacitor,

#f#=frequency of applied voltage.

#X_cprop1/f#[since#1/(2piC)=#constant]#" "color(blue)((1))#

From ohm's law,

#V=I_cX_c#

#X_c=V/I_c#

#X_cprop1/I_c#[since V is constant]#" "color(blue)((2))#

From #" "color(blue)((1))#&#color(blue)((2))#;

#1/fprop1/I_C#

#color(green)(I_cpropf)#

From above relation,

If the frequency of voltage is decreased, then current value is also #color(blue)(decreased)#.