An e.m.f. E = 4cos (1000t) volt is applied to an LR circuit of inductance 3 mH and resistance 4 Ω. The maximum current in the circuit is (a) 4/√(7) A (b) 1.0 A (c) 4/7 A (d) 0.8 A

Answer: (d). From E = 4cos (1000t): E₀ = 4 V, ω = 1000 rad/s. XL = ω L = 1000 × 3×10⁻³ = 3 Ω Z = √(R² + XL²) = √(16 + 9) = 5 Ω I₀ = E₀/Z = 4/5 = 0.8 A So the answer is (d) 0.8 A.

An e.m.f. E = 4cos (1000t) volt is applied to an LR circuit of… | MHT CET 2023 (9 May, Shift 2)

Q34MHT CET 2023 · 9 MAY · SHIFT 2Easy

RL and RC Series Circuits

An e.m.f. $E = 4\cos(1000t)$ volt is applied to an LR circuit of inductance $3\text{ mH}$ and resistance $4\ \Omega$ . The maximum current in the circuit is

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Answer: (d)

From $E = 4\cos(1000t)$ : $E_0 = 4\text{ V}$ , $\omega = 1000\text{ rad/s}$ .
$X_L = \omega L = 1000 \times 3\times10^{-3} = 3\ \Omega$
$Z = \sqrt{R^2 + X_L^2} = \sqrt{16 + 9} = 5\ \Omega$
$I_0 = \frac{E_0}{Z} = \frac{4}{5} = 0.8\text{ A}$
So the answer is (d) $0.8\text{ A}$ .

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RL and RC Series Circuits question from MHT CET 2023 (9 May, Shift 2)

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