Category: Part 3: Electricity

  • Problem 3.176 — Magnetostatics and magnetic forces

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.176 — 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 3.138 — Magnetic pressure in a solenoid

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.138. At $B=25.1\,\text{mT}$: $P_B = B^2/(2\mu_0) = 251\,\text{Pa}$. Total radial force on cylinder of length $L$: $F = P_B\times2RL = 12.6\,\text{N}$. Given Information Current $I$ or charge $q$ and velocity $v$ as given Geometry (straight wire, loop, solenoid) as specified Permeability of free space $\mu_0 =…

  • Problem 3.273 — Electromagnetic induction

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.273 — 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 3.136 — Magnetic force on dipole in non-uniform field

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.136. $$\mathbf{F} = \nabla(\mathbf{m}\cdot\mathbf{B}) = m\frac{\partial B_z}{\partial z}\hat{z}$$ Dipole attracted to regions of stronger field. Given Information Current $I$ or charge $q$ and velocity $v$ as given Geometry (straight wire, loop, solenoid) as specified Permeability of free space $\mu_0 = 4\pi\times10^{-7}\,\text{T m A}^{-1}$ Physical Concepts &…

  • Problem 3.271 — Electromagnetic induction

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.271 — 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 3.92 — Continuity equation

    Problem Statement Irodov Problem 3.92. 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 3.175 — Magnetostatics and magnetic forces

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.175 — 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 3.135 — Hysteresis in ferromagnets

    Problem Statement Irodov Problem 3.135. 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 3.91 — Battery capacity and discharge

    Problem Statement Analyze the circuit: Irodov Problem 3.91. $C=60\,\text{Ah}$: $Q=216\,\text{kC}$, $U=720\,\text{Wh}$. At 5 A: $t=12\,\text{h}$, $P=V_t\times I = 57.5\,\text{W}$. 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 $V = IR$ and Kirchhoff’s two laws are…

  • Problem 3.270 — Electromagnetic induction

    Problem Statement Solve the magnetic field/force problem: Irodov Problem 3.270 — 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…