Category: Part 3: Electricity

  • Problem 3.130 — Neumann formula for mutual inductance

    Problem Statement Irodov Problem 3.130. Given Information All quantities, constants, and constraints stated in the problem above Physical constants used as needed (see Concepts section) Physical Concepts & Formulas This problem draws on fundamental physical principles. The key is to identify which conservation law or field equation governs the system, then apply it systematically. Dimensional…

  • Problem 3.265 — Electromagnetic induction

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.265 — Electromagnetic induction. This problem belongs to the section on Electromagnetic induction . Key principles: Faraday: $\mathcal{E} = -d\Phi/dt$; Lenz; motional EMF; inductance The solution proceeds by identifying the relevant physical configuration, applying the governing law Given Information Current $I$ or charge $q$ and velocity…

  • Problem 3.86 — Contact (spreading) resistance

    Problem Statement Analyze the circuit: Irodov Problem 3.86. $$R_{\text{contact}} = \rho/(\pi a)$$ for circular contact of radius $a$. Independent of conductor size; dominates in small contacts. Given Information Resistance values $R_1, R_2, \ldots$ as specified EMF $\mathcal{E}$ and internal resistance $r$ of battery Any additional circuit elements given Physical Concepts & Formulas Ohm’s Law $V…

  • Problem 3.169 — Magnetostatics and magnetic forces

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.169 — Magnetostatics and magnetic forces. Key law: $B_{\text{wire}} = \mu_0 I/(2\pi r)$, torque $\tau = mB\sin\theta$, force $F = qvB\sin\theta$ This problem from the Magnetostatics and magnetic forces section requires applying the governing equation with the given geometry and nume Given Information Current $I$ or…

  • Problem 3.83 — Ohmmeter: resistance measurement

    Problem Statement Analyze the circuit: Irodov Problem 3.83. Mid-scale reading = internal resistance $R_0 = \mathcal{E}/I_g$. At half deflection: $R_x = R_0 = \boxed{1500\,\Omega}$. Given Information Resistance values $R_1, R_2, \ldots$ as specified EMF $\mathcal{E}$ and internal resistance $r$ of battery Any additional circuit elements given Physical Concepts & Formulas Ohm’s Law $V = IR$…

  • Problem 3.166 — Magnetostatics and magnetic forces

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.166 — Magnetostatics and magnetic forces. Key law: $B_{\text{wire}} = \mu_0 I/(2\pi r)$, torque $\tau = mB\sin\theta$, force $F = qvB\sin\theta$ This problem from the Magnetostatics and magnetic forces section requires applying the governing equation with the given geometry and nume Given Information Current $I$ or…

  • Problem 3.128 — Lenz’s law: pulling a loop out of field

    Problem Statement Irodov Problem 3.128. Given Information All quantities, constants, and constraints stated in the problem above Physical constants used as needed (see Concepts section) Physical Concepts & Formulas This problem draws on fundamental physical principles. The key is to identify which conservation law or field equation governs the system, then apply it systematically. Dimensional…

  • Problem 3.263 — Electromagnetic induction

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.263 — Electromagnetic induction. This problem belongs to the section on Electromagnetic induction . Key principles: Faraday: $\mathcal{E} = -d\Phi/dt$; Lenz; motional EMF; inductance The solution proceeds by identifying the relevant physical configuration, applying the governing law Given Information Current $I$ or charge $q$ and velocity…

  • Problem 3.84 — Energy balance in a circuit

    Problem Statement Analyze the circuit: Irodov Problem 3.84. Source $P = \mathcal{E}I = 2400\,\text{J}$. $Q_R = 2160\,\text{J}$, $Q_r = 240\,\text{J}$. Efficiency $= R/(R+r) = 90\%$. Given Information Resistance values $R_1, R_2, \ldots$ as specified EMF $\mathcal{E}$ and internal resistance $r$ of battery Any additional circuit elements given Physical Concepts & Formulas Ohm’s Law $V =…

  • Problem 3.167 — Magnetostatics and magnetic forces

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.167 — Magnetostatics and magnetic forces. Key law: $B_{\text{wire}} = \mu_0 I/(2\pi r)$, torque $\tau = mB\sin\theta$, force $F = qvB\sin\theta$ This problem from the Magnetostatics and magnetic forces section requires applying the governing equation with the given geometry and nume Given Information Current $I$ or…