Structure of Atom — Chemistry STD 11 Science — Question
Maharashtra BoardEnglish MediumSTD 11 ScienceChemistryStructure of Atom4 Marks
Question
Write a note on Heisenberg’s uncertainty principle.
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Answer
i. Uncertainty principle was proposed by Wemer Heisenberg in 1927 . It can be stated as "It is impossible to determine simultaneously, the exact position and exact momentum (or velocity) of an electron ". ii. If $\Delta x$ is the uncertainty in the determination of the position of a very small moving particle and $\Delta \mathrm{px}$ is the uncertainty in the determination of its momentum, then $\Delta \mathrm{x} \Delta \mathrm{p}_{\mathrm{x}} \geq \frac{\mathrm{h}}{4 \pi}$ $\qquad$ ..(1) where $h$ is Planck's constant iii. The above equation can alternatively be stated as, $\Delta \mathrm{x} \times \mathrm{m} \times \Delta \mathrm{v}_{\mathrm{x}} \geq \frac{\mathrm{h}}{4 \pi}$, because $\Delta \mathrm{p}_{\mathrm{x}}=\mathrm{m} \times \Delta \mathrm{v}_{\mathrm{x}}$ $\qquad$ where $\Delta v_x$ is the uncertainty in the determination of velocity and $m$ is the mass of the particle.
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