Plancks Constant Apparatus

Product Code : EL-PLE-13149Eduscope India is a leading Plancks Constant Apparatus Quick Answer: Planck's Constant Apparatusdetermines Planck's constant experimentally through the photoelectric effect, using a cesium photocathode and a nanoammeter.

Light striking the apparatus's cesium photocathode ejects electrons, but only when the light's frequency is above a threshold value; measuring how the stopping voltage needed to halt these ejected electrons varies with the light's frequency lets Planck's constant — currently accepted at approximately 6.626 x 10^-34 J.s — be determined directly, a real and historically significant method explained by Albert Einstein in 1905 and cited in his 1921 Nobel Prize in Physics. Three components make the measurement reliable: an enclosed vacuum photocell housing the cesium photocathode, which keeps ejected electrons from being scattered by air molecules, and an attachment for illuminating it with light of known frequency; a high-stability power supply that sweeps a variable stopping voltage until it just cancels the photocurrent at a given frequency; and a nanoammeter sensitive enough to measure the resulting very small photocurrents. Alongside Planck's constant, this Planck constant experiment kit apparatus also estimates the work function of cesium — the minimum energy needed to eject an electron from its surface — to less than 5% error.

It is part of EduScope India'sPhysics Lab Equipmentrange, and is a natural companion to theFranck-Hertz Apparatus IIand theHall Effect Apparatusfor a broader hands-on foundation in modern physics.