Physics Ncert Solutions Class 12th Class 12th Physics Alternating Current

In AC circuit with source voltage e = 20 sin 1000 t is connected to series L – R circuit whose power factor is $\frac{1}{\sqrt[]{2}}$ . If E = 25 sin 2000 t, the new power factor is

Option 1 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mfrac> <mrow> <mn>2</mn> </mrow> <mrow> <mroot> <mrow> <mn>5</mn> </mrow> <mrow></mrow> </mroot> </mrow> </mfrac> </mrow> </math> </span></p>

Option 2 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mfrac> <mrow> <mn>1</mn> </mrow> <mrow> <mroot> <mrow> <mn>5</mn> </mrow> <mrow></mrow> </mroot> </mrow> </mfrac> </mrow> </math> </span></p>

Option 3 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mfrac> <mrow> <mn>1</mn> </mrow> <mrow> <mroot> <mrow> <mn>3</mn> </mrow> <mrow></mrow> </mroot> </mrow> </mfrac> </mrow> </math> </span></p>

Option 4 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mroot> <mrow> <mfrac> <mrow> <mn>3</mn> </mrow> <mrow> <mn>5</mn> </mrow> </mfrac> </mrow> <mrow></mrow> </mroot> </mrow> </math> </span></p>

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Answered by

Alok Kumar Singh | Contributor-Level 10

4 months ago

Correct Option - 2

Detailed Solution:

Lω = 1000 L Lω = R.

New

R = 1000 L

2000 L

$c o s θ = \frac{R}{Z}$

$= \frac{1000 L}{\sqrt[]{{(1000 L)}^{2} + {(2000 ? L)}^{2}}}$

$= \frac{1}{\sqrt[]{1 + 4}} = \frac{1}{\sqrt[]{5}}$

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$I = Q_{0 . ω}$

$= \frac{C V}{\sqrt[]{L C}} = V \sqrt[]{\frac{C}{L}}$

$= 12 \sqrt[]{\frac{100 \times 1 0^{- 6}}{10 \times 1 0^{- 3}}}$

= 1.2 A

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Physics Ncert Solutions Class 12th 2023

Physics Ncert Solutions Class 12th 2023

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