KCET · Physics · Alternating Current
A light bulb rated \(100\) W is connected to an AC source of \(220\) V, \(50\) Hz. The rms current through the bulb is
- A \(0.454\) A
- B \(0.545\) A
- C \(2.20\) A
- D \(0.22\) A
Answer & Solution
Correct Answer
(A) \(0.454\) A
Step-by-step Solution
Detailed explanation
The power of the light bulb is given as \(P = 100\) W.
The rms voltage of the AC source is \(V_{rms} = 220\) V.
For a purely resistive load like a light bulb, the power factor is \(1\). The average power is given by the relation:
\(P = V_{rms} I_{rms}\)
Rearranging the formula to solve for the rms current \(I_{rms}\):
\(I_{rms} = \dfrac{P}{V_{rms}}\)
Substituting the given values:
\(I_{rms} = \dfrac{100}{220}\)
\(I_{rms} = \dfrac{5}{11} \approx 0.454\) A
Answer: \(0.454\) A
The rms voltage of the AC source is \(V_{rms} = 220\) V.
For a purely resistive load like a light bulb, the power factor is \(1\). The average power is given by the relation:
\(P = V_{rms} I_{rms}\)
Rearranging the formula to solve for the rms current \(I_{rms}\):
\(I_{rms} = \dfrac{P}{V_{rms}}\)
Substituting the given values:
\(I_{rms} = \dfrac{100}{220}\)
\(I_{rms} = \dfrac{5}{11} \approx 0.454\) A
Answer: \(0.454\) 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
- When electron jumps from \( n=4 \) level to \( n=1 \) level, the angular momentum of electron
changes byKCET 2016 Easy - An aluminium sphere is dipped into water. Which of the following is true?KCET 2019 Medium
- Effective resistance between \( A \) and \( B \) in the following circuit
KCET 2016 Hard - In a nuclear reactor heavy nuclei is not used as moderators becauseKCET 2021 Hard
- In Faraday-Henry's experiment, a coil is connected to a galvanometer. For the deflection of pointer in the galvanometer, which of the following statement/s is/are WRONG?
The pointer in the galvanometer deflects -
(a) When the bar magnet is moved towards the stationary coil along its axis.
(b) When the bar magnet is moved away from the stationary coil along its axis.
(c) When the coil is moved towards the stationary bar magnet along its axis.
(d) When the coil and the magnet are moved without relative motion between them.KCET 2026 Easy - The image formed by an objective lens of a compound microscope isKCET 2025 Easy
More PYQs from KCET
- The domain of \(f(x)=\sin ^{-1}\left[\log _{2}\left(\frac{x}{2}\right)\right]\) isKCET 2011 Easy
- \(9.65 \mathrm{C}\) of electric current is passed through fused alhydrous \(\mathrm{MgCl}_{2}\). The magnesium metal thus obtained is completely converted into a Grignard reagent. The number of moles of Grignard reagent obtained isKCET 2011 Medium
- Equation of the plane perpendicular to the line \( \frac{x}{1}=\frac{y}{2}=\frac{z}{3} \) and passing through the point \( (2, \),
\( 3,4) \) isKCET 2014 Easy - Which one of the following is incorrect about cancer cells?KCET 2014 Medium
- Gynecomastia is a symptom ofKCET 2022 Easy
- If \(x^{x}=y^{y}\), then \(\frac{d y}{d x}\) isKCET 2007 Medium