🔍 Key Concepts

• Difference between low pressure sodium (SOX) and high pressure sodium (SON) lamps • How the illustration labels each circuit and lamp type (MBF, SOX, SON) next to A, B, C, and D • Typical physical shape of a low pressure sodium lamp and its special arc tube design for sodium retention

💭 Think About

• Look at the labels written next to each circuit (MBF Lamp Circuit, SOX Lamp Circuit, SON Lamp Circuit). Which one corresponds to low pressure sodium? • Compare the long tubular lamp with the U‑shaped arc tube and sodium retention dimples to the more bulb‑shaped high pressure design. Which construction matches low pressure operation? • Match the textual description on the drawing (for example, mentions of sodium retention and glass coating) to what you know about low pressure sodium lamps.

✅ Before You Answer

• Verify which lettered figure (A, B, C, or D) is explicitly associated with the SOX lamp circuit in the diagram. • Confirm that the lamp you choose has a long narrow tube and a U‑shaped arc tube designed for sodium retention, which is characteristic of low pressure sodium. • Double‑check that the remaining sodium lamp in the choices is labeled SON, which corresponds to high pressure sodium and should NOT be selected.