question_answer 126)

  The effect of uncertainty principle is significant only for motion of microscopic particles and is negligible for the macroscopic particles. Justify the statement with the help of a suitable example.

Answer:

  Just like de Broglie equation, uncertainty principle has no real significance in our daily life, i.e., in the macroscopic world. It is due to the fact that the energy of a photon is insufficient to change the position and velocity of macroscopic objects, e.g., a cricket ball, motor car, etc. In a playground a floodlight is unable to change the position and velocity of a cricket ball. Thus, in our daily life, the impact of uncertainty principle is insignificant. In the case of bigger particles (having considerable mass), the value of uncertainty product is negligible. Uncertainty principle is important only in the case of smaller moving particles like electrons. For an electron of mass\[m(9.1\times {{10}^{-28}}g)\], the product of uncertainty is quite large. \[\Delta x\Delta \upsilon \ge \frac{h}{4\pi m}\] \[\ge \frac{6.626\times {{10}^{-27}}}{4\times 3.14\times 9.1\times {{10}^{-28}}}\] \[=0.57\] erg sec per gram approximately.