Question 472: AC fundamentals

Question

A series R-C circuit is connected to an alternating voltage source. Consider two situations : 
(a)  When capacitor is air filled. 
(b)  When capacitor is mica filled. 
Current through resistor is $$I$$ and voltage across capacitor is $$V$$ then

Accepted Answer

For series R Ã¢ÂÂ C circuit, capacitive reactance,
Z= $$\sqrt {{R^2} + {{\left( {{1 \over {C\omega }}} ight)}^2}} $$
Current through resistor, i = Current in the circuit
= $${V \over {{Z_c}}} = {V \over {\sqrt {{R^2} + {{\left( {{1 \over {C\omega }}} ight)}^2}} }}$$
Voltage across capacitor, V = iX
C
= $$ {V \over {\sqrt {{R^2} + {{\left( {{1 \over {C\omega }}} ight)}^2}} }} 	imes {1 \over {C\omega }}$$
= $${V \over {\sqrt {{R^2}{\omega ^2}{C^2} + 1} }}$$
When mica is introduced capacitance will increase, hence voltage across capacitor gets decrease.

Answer

$${i_a} > {i_b}$$

Answer

$${V_a} = {V_b}$$

Answer

$${V_a} < {V_b}$$

Answer

$${V_a} > {V_b}$$

AC fundamentals

A series R-C circuit is connected to an alternating voltage source. Consider two situations : (a) When capacitor is air filled. (b) When capacitor is mica filled. Current through resistor is $I and voltage across capacitor is V$ then

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