SATHEE: alternating-currents Question 26

alternating-currents Question 26

Question: Q. 15. (i) When an $a c$ source is connected to an ideal capacitor show that the average power supplied by the source over a complete cycle is zero.

(ii) A lamp is connected in series with a capacitor. Predict your observation when the system is connected first across a $d c$ and then an $a c$ source. What happens in each case if the capacitance of the capacitor is reduced?

A&E [Delhi Comptt. I, II, III 2013]

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Solution:

Ans. (i) When an ideal capacitor is connected with $a c$ source, the current flow continuously but due to dielectric in between the plates of capacitor, there is no current, i.e.,

$\begin{aligned} I_{a v g} = 0 & ∴ P_{a v g} = V \times I_{a v g} & P_{a v g} = 0 \end{aligned}$

(ii) For $d c$ , lamp will not shine as capacitor blocks $d c$ even if we reduce the capacitance, the lamp will not shine.

$1$

Lamp will shine, if $a c$ is used on reducing $C$ , with increase of impedance.

Hence, lamp will shine less brightly.

Alternating Currents

alternating-currents Question 26

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Alternating Currents

alternating-currents Question 26

Long Answer Type Questions

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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