PHOTOMETRIC Principal and task: The luminous intensity emitted by a punctual source is deter mined as a function of distance. PROBLEMS: 1. The luminous intensity emitted by a punctual source is determined as a function of distance from the source. 2. The photometric law of distance is verified by plotting illuminance as a function of the reciprocal value of the square of the distance.
PHOTOMETRIC The aim of photometry experiment ▸ The luminous intensity I emitted by a punctual source is determined as a function of distance from the source. ▸ The photometric law of distance is verified by plotting illuminance as a function of the reciprocal value of the square of the distance.
PHOTOMETRIC Experimental set-up ▸ Switch on the luxmeter and measure the background illuminance E 0. ▸ Set the separation r between the probe and lamp to 55 cm. ▸ Switch on the lamp and measure the illuminance E. ▸ Decreasing the separation in steps of 5 cm, record E until you reach a separation of r = 25 cm.
FORTH EXPERIMENT
Lloyd’s Mirror
Objective Understand the nature of sound-waves and calculate the frequency of ultrasonic sound−waves by Lloyd’s Mirror Interference.
Schematic representation of the interference setup