KCET · Physics · Alternating Current
An ideal choke draws a current of \(8 \mathrm{~A}\) when connected to an AC supply of \(100 \mathrm{~V}, 50 \mathrm{~Hz}\). A pure resistor draws a current of \(10 \mathrm{~A}\) when connected to the same source. The ideal choke and the resistor are connected in series and then connected to the AC source of \(150 \mathrm{~V}, 40 \mathrm{~Hz}\). The current in the circuit becomes
- A \(\frac{15}{\sqrt{2}} \mathrm{~A}\)
- B \(8 \mathrm{~A}\)
- C \(18 \mathrm{~A}\)
- D \(10 \mathrm{~A}\)
Answer & Solution
Correct Answer
(A) \(\frac{15}{\sqrt{2}} \mathrm{~A}\)
Step-by-step Solution
Detailed explanation
Resistance, \(\mathrm{R}=\frac{100}{10}=10 \Omega\)
Inductive reactance, \(\mathrm{X}_{\mathrm{L}}=2 \pi \mathrm{fL}\)
\(\frac{100}{8}=2 \pi \times 50 \times \mathrm{L} \)
\(\Rightarrow \mathrm{L}=\frac{1}{8 \pi} \mathrm{H} \)
\(\mathrm{X}_{\mathrm{L}}^{\prime}=2 \pi \mathrm{f}^{\prime} \mathrm{L}=2 \pi \times 40 \times \frac{1}{8 \pi}=10 \Omega\)
Impedance of the circuit is \(\mathrm{Z}=\sqrt{\mathrm{R}^{2}+\mathrm{X}_{\mathrm{L}}^{\prime 2}}\)
\(=\sqrt{(10)^{2}+(10)^{2}}=10 \sqrt{2} \Omega\)
Current in the circuit is \(\mathrm{i}=\frac{\mathrm{V}}{\mathrm{Z}}=\frac{150}{10 \sqrt{2}}=\frac{15}{\sqrt{2}} \mathrm{~A}\)
Inductive reactance, \(\mathrm{X}_{\mathrm{L}}=2 \pi \mathrm{fL}\)
\(\frac{100}{8}=2 \pi \times 50 \times \mathrm{L} \)
\(\Rightarrow \mathrm{L}=\frac{1}{8 \pi} \mathrm{H} \)
\(\mathrm{X}_{\mathrm{L}}^{\prime}=2 \pi \mathrm{f}^{\prime} \mathrm{L}=2 \pi \times 40 \times \frac{1}{8 \pi}=10 \Omega\)
Impedance of the circuit is \(\mathrm{Z}=\sqrt{\mathrm{R}^{2}+\mathrm{X}_{\mathrm{L}}^{\prime 2}}\)
\(=\sqrt{(10)^{2}+(10)^{2}}=10 \sqrt{2} \Omega\)
Current in the circuit is \(\mathrm{i}=\frac{\mathrm{V}}{\mathrm{Z}}=\frac{150}{10 \sqrt{2}}=\frac{15}{\sqrt{2}} \mathrm{~A}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- According to Einstein's photoelectric equation, the graph of \(\mathrm{KE}\) of the photoelectron emitted from the metal versus the frequency of the incident radiation gives a straight line graph, whose slopeKCET 2010 Easy
- White light reflected from a soap film (Refractive Index \(=1.5\) ) has a maxima at \(600 \mathrm{~nm}\) and a minima at \(450 \mathrm{~nm}\) with no minimum in between. Then the thickness of the film isKCET 2013 Medium
- A source of frequency \(\nu\) gives \(6\) beats/second when sounded with a source of frequency \(200\) Hz. The second Harmonic of frequency \(2\nu\) of the source gives \(8\) beats/second when sounded with a source of frequency \(420\) Hz. The value of \(\nu\) isKCET 2026 Medium
- Maximum diffraction takes place in a given slit forKCET 2008 Easy
- Pick out the statement which is incorrect.KCET 2015 Easy
- A body of mass \(m\) moving along a straight line covers half the distance with a speed of \(2 \mathrm{~ms}^{-1}\). The remaining half of the distance is covered in two equal time intervals with a speed of \(3 \mathrm{~ms}^{-1}\) and \(5 \mathrm{~ms}^{-1}\) respectively. The average speed of the particle for the entire journey isKCET 2009 Medium
More PYQs from KCET
- The moment of inertia of a circular ring of radius \(\mathrm{r}\) and mass \(\mathrm{M}\) about diameter isKCET 2009 Easy
- A point object \(O\) is placed in front of a glass rod having spherical end of radius of curvature \(30 \mathrm{~cm}\). The image would be formed at
KCET 2010 Easy - A galvanometer of resistance \( 50 \Omega \) gives a full scale deflection for a current \( 5 \times 10^{-4} \mathrm{~A} \). The resistance that should be connected in series with the galvanometer to read \( 3 \mathrm{~V} \) isKCET 2015 Medium
- A point charge \(A\) of \(+10 \mu \mathrm{C}\) and another point charge \(B\) of \(+20 \mu \mathrm{C}\) are kept 1 m apart in free space. The electrostatic force on \(A\) due to \(B\) is \(\mathbf{F}_1\) and the electrostatic force on \(B\) due to \(A\) is \(\mathbf{F}_2\). ThenKCET 2024 Medium
- If \(A\) is a square matrix, such that \(A^2=A\) then \((I+A)^3\) is equal toKCET 2024 Easy
- Which of the following is not a colligative property?KCET 2013 Easy