🔍 Key Concepts

• Note the labels unknown resistor (Rₓ) and standard resistor (Rₛ) in the left branch of the schematic. • The right-hand side shows a ratio arm (R₁/R₂) and a sensitive meter (G), forming a bridge circuit. • Consider what quantity is typically found by balancing a bridge so that no current flows through the meter.

💭 Think About

• What type of electrical quantity do components labeled Rₓ, Rₛ, R₁, and R₂ normally represent in circuit diagrams? • In a bridge circuit, when the meter (G) reads zero, what relationship between the left and right branches allows you to solve for the unknown component? • Which answer choice matches what you would determine by comparing an unknown component to a standard one using a bridge and a ratio arm?

✅ Before You Answer

• Identify what the symbol R usually denotes in circuit notation and match that to one of the answer choices. • Confirm that the instrument uses a bridge balance (meter at zero) rather than measuring current over time or magnetic field strength. • Eliminate any options that are not typically measured with a four-arm bridge using only passive resistive components and a galvanometer.