The uncertainty in the position of an electron (mass 9.1 × 10^–28g) moving with a velocity of 3.0 × 10⁴cm^–1 accurate up to 0.011%, will be

$∆\mathrm{x} =\frac{\mathrm{h}}{4\mathrm{\pi m} \times ∆\mathrm{v}}$

Mass = 9.1 × 10^–28 gm ; velocity =3.0$\times$10⁴cm^-1 , accurate upto 0.011 %

so $∆\mathrm{v}$ =$\frac{3.0\times {10}^4\times 0.011}{100}$;h =6.625$\times$10^-27

$∆\mathrm{x} =\frac{6.625 \times {10}^{-27}\times 100}{4\times 3.14\times 9.11\times {10}^{-28} \times 3.0\times {10}^4\times 0.011}$=0.175 cm