Multiple Choice Questions

This guide organizes advice from past students who got 4s and 5s on their exams. We hope it gives you some new ideas and tools for your study sessions. But remember, everyone's different—what works for one student might not work for you. If you've got a study method that's doing the trick, stick with it. Think of this as extra help, not a must-do overhaul.

💭 General Advice

• Begin Early and Practice with Timing: Start your preparation early in the school year and frequently time yourself while completing practice problems to get used to the pace of the actual exam.
• Conceptual Understanding Through Derivation: Spend time understanding and deriving the formulas related to electromagnetism and electric circuits. A deep understanding of these formulas can greatly aid in solving complex problems.
• Strategy Over Memorization: While memorizing formulas can be helpful, focus on understanding the concepts and strategies behind solving problems. This will enable you to tackle new and challenging questions more effectively.
• Process of Elimination: Use the process of elimination on multiple-choice questions. Narrowing down your choices increases your chances of selecting the correct answer.

🫧 Before You Bubble

• Preview the Questions: Quickly skim through the questions before starting to answer them. This will help you allocate your time more effectively, allowing you to spend more time on complex questions.
• Identify Key Information: Before solving, identify and underline key information and what the question is specifically asking. This practice helps in selecting the correct formula and approach.

🤔 Choosing the Best Answer

• Ensure Logical Consistency: Always double-check that your chosen answer makes sense in the context of the question. Beware of answers that defy basic principles of physics.
• Back-Check with Equations: If uncertain, use the relevant equations to check if your selected answer is plausible.

📝 Using Your Formula Sheet

• Familiarize, Don't Rely: Become familiar with the formulas before the exam. The formula sheet should mainly be used for reference or to double-check during the exam.
• Understand the Formulas: Spend time understanding each formula on the sheet, including its derivation and application. This knowledge will speed up your problem-solving process.

➗Essential Equations and Concepts

• Coulomb's Law: $F=k\cdot\frac{q_1 q_2}{r^2}$, where $F$ is the force between two charges, $q_1$ and $q_2$ are the magnitudes of the charges, $r$ is the distance between the centers of the two charges, and $k$ is Coulomb’s constant.
• Electric Field: $E = \frac{F}{q}=k\frac{|q|}{r^2}$, where $E$ is the electric field created by charge $q$ at a distance $r$.
• Gauss's Law: $\Phi E= \frac{Q}{\epsilon_0}$, where $\Phi E$ is the electric flux through a closed surface enclosing any volume, $Q$ is the total charge enclosed by the surface, and $\epsilon_0$ is the electric constant.
• Capacitance: $q=\frac{C}{V}$, where $C$ is the capacitance, $q$ is the charge, and $V$ is the voltage.
• Ohm's Law: $V=IR$, where $V$ is the voltage across a conductor, $I$ is the current through the conductor, and $R$ is the resistance of the conductor.
• Magnetic Field due to a Long Straight Conductor: $B=\frac{\mu_o I}{2\pi r}$, where $B$ is the magnetic field, $\mu_o$ is the magnetic constant, $I$ is the current, and $r$ is the distance from the conductor.
• Ampère’s Law: $\int B\ \text{d}l=\mu_oI$, where the line integral of the magnetic field ($B$) around a closed path is equal to the permeability of free space ($\mu_o$) times current ($I$).
• Faraday's Law of Electromagnetic Induction: $\epsilon=-N \frac{\Delta \Phi}{\Delta t}$, where $\epsilon$ is the induced voltage, $N$ is the number of loops, $\Delta \Phi$ is the change in magnetic flux, and $\Delta t$ is the change in time.

🤔 Common Mistakes

• Units and Dimensions: Always check that your final answer has the correct units. This can also help in cross-verifying the answers.
• Sign Conventions: Pay close attention to the sign conventions, especially in electric and magnetic fields. Incorrect signs can lead to incorrect answers.
• Boundary Conditions: In problems involving conductors and dielectrics, carefully consider the boundary conditions. Misinterpreting these can lead to errors in calculating electric fields and potentials.
• Assumptions in Circuit Problems: Do not make unwarranted assumptions in circuit problems. Analyze each component's role in the circuit carefully, especially in complex circuits with multiple loops and nodes.