OBJECT: To determine by means of a photometer the relationship between the efficiency of an incandescent lamp and the potential drop across it.
METHOD: A standard lamp and a test lamp are placed at opposite ends of a photometer bench. By adjusting the position of a photometer box so that its screen is equally illuminated on the two sides, the candle power of the test lamp is determined. This is repeated for various voltages on the test lamp and the relationship between the voltage and efficiency (candles per watt) determined.
