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CBSE Class 12 Physics 2023 Outside Delhi Set 2 Paper

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Question : 11 of 13
Marks: +1, -0
SECTION - C
A series RLR L circuit with R=10 ΩR=10\,\Omega and L=(100π) mHL=\left(\frac{100}{\pi}\right)\,\text{mH} is connected to an ac source of voltage V=141 sin⁡V=141\,\sin (100πt)(100\pi t), where VV is in volts and tt is in seconds. Calculate
(a) impedance of the circuit
(b) phase angle, and
(c) voltage drop across the inductor
(a) Given, R=10 ΩR=10\,\Omega
L=(100π) mHL=\left(\frac{100}{\pi}\right)\,\text{mH}
V=141sin⁡(100πt)V=141\sin(100\pi t)
Impedance=Z=R2+(ωL)2\text{Impedance}=Z=\sqrt{R^2+(\omega L)^2}
Or, Z=102+(100π×100π×10−3)2Z=\sqrt{10^2+\left(100\pi \times \frac{100}{\pi} \times 10^{-3}\right)^2}
Or, Z=102+102Z=\sqrt{10^2+10^2}
∴ Z=102 ΩZ=10\sqrt{2}\,\Omega
(b) Phase angle=tan⁡−1ωLR\text{Phase angle}=\tan^{-1}\frac{\omega L}{R}
Or, Phase angle =tan⁡−1(100π×100π×10−310)=\tan^{-1}\left(\frac{100\pi \times \frac{100}{\pi} \times 10^{-3}}{10}\right)
Or,     \;\; Phase angle =tan⁡−11=\tan^{-1}1
∴\therefore Phase angle =45∘=45^{\circ}
(c) V0=141 VV_0=141\,\text{V}
XL=ωLX_L=\omega L
=100π×100π×10−3=100\pi \times \frac{100}{\pi} \times 10^{-3}
=10 Ω=10\,\Omega
I0=V0Z=141102I_0=\frac{V_0}{Z}=\frac{141}{10\sqrt{2}}
Voltage drop across inductor =VL=I0XL=V_L=I_0 X_L
Or, VL=141102×10\text{Or, } V_L=\frac{141}{10\sqrt{2}} \times 10
∴VL=100 V\therefore V_L=100\,\text{V}
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