LED Array can be used to study the relation between light colour and wavelength. Planck’s constant can also be determined by knowing voltage & the wavelength across different colour LEDs.

Features:
Eleven different color LEDs with different wavelength are mounted in a vertical column. 140 x 80 x 268 mm.
Rotary switch is provided to select any individual LED or all together.
4mm safety sockets are provided to check the voltage across individual LED.
Input 5V DC, 1.5 Amp Power Adaptor.

How colour affects wavelength. A major improvement over using colour filters. Students can easily observe colour diffraction from their seats and actually compare the diffraction patterns for each colour. Invaluable for determining frequencies.