Q51. Based on Heisenberg's uncertainty principle, the uncertainty in the velocity of the electron to be found within an atomic nucleus of diameter $10 ^ { - 15 } \mathrm {~m}$ is $\_\_\_\_$ $.10 ^ { 9 } \mathrm {~ms} ^ { - 1 }$ (nearest integer) [Given : mass of electron $= 9.1 \times 10 ^ { - 31 } \mathrm {~kg}$, Plank's constant $\left. ( h ) = 6.626 \times 10 ^ { - 34 } \mathrm { Js } \right]$ (Value of $\pi = 3.14$ )