Planck'S Constant Apparatus Standard Model

BESTO Planck's constant Appt. is an instrument to obtain Planck's Constant. A suitable light source provides light energy to photo tube. Three different colours of filters are used is between light source & photo tube to select the different wavelength. A vacuum photo tube is kept inside the tube housing. DC variable regulated power supply of 0-1V, provides stopping potential for electrodes & the ammeter gives accurate current output (in range of few microamperes ) measurement facility. The stopping potential
is measured by varying the anode voltage, untill current drops to zero.The lamp house, photo tube housing with arrangement for fixing filter are placed on wooden Planck's of 40cm long.