Test Index

CBSE Class 12 Physics 2022 Term 2 Outside Delhi Set 3 Solved Paper

© examsnet.com
Question : 5 of 5
Marks: +1, -0
(a) The energy of hydrogen atom in an orbit is −1.51 eV-1.51\,\text{eV}. What are kinetic and potential energies of the electron in this orbit?
(b) The electron in a hydrogen atom is typically found at a distance of about 5.3×10−11 m5.3 \times 10^{-11}\,\text{m} from the nucleus which has a diameter of about 1.0×10−15 m1.0 \times 10^{-15}\,\text{m}. Assuming the hydrogen atom to be a sphere of radius 5.3×10−11 m5.3 \times 10^{-11}\,\text{m}, what fraction of its volume is occupied by the nucleus?
Solution:  
(a) Total energy =−1.51 eV= -1.51\,\text{eV}
So, Potential energy =2×= 2\times Total energy
=−3.02 eV= -3.02\,\text{eV}
Kinetic energy =−= - Total energy
=1.51 eV= 1.51\,\text{eV}
(b) Volume of nucleus =43Ï€R3= \frac{4}{3}\pi R^3
Volume of atom =43Ï€R3= \frac{4}{3}\pi R^3
Fraction of volume occupied by the nucleus ==
43πr343πR3=(0.5×10−15)3(5.3×10−11)3=8.39=8.4×10−16\frac{\frac{4}{3}\pi r^3}{\frac{4}{3}\pi R^3} = \frac{(0.5 \times 10^{-15})^3}{(5.3 \times 10^{-11})^3} = 8.39 = 8.4 \times 10^{-16}
© examsnet.com
Go to Question:
Prev Question