Question

An electron has a mass of $9.1\times {10}^{-31}kg$. It revolves round the nucleus in a circular orbit of radius $0.529\times {10}^{-10}$ metre at a speed of $2.2\times {10}^{6}m/s$. The magnitude of its linear momentum in this motion is

• A. $1.1\times {10}^{-34}kg-m/s$
• B. $2.0\times {10}^{-24}kg-m/s$
• C. $4.0\times {10}^{-24}kg-m/s$
• D. $4.0\times {10}^{-31}kg-m/s$

Answer 1

The correct option is B $2.0\times {10}^{-24}kg-m/s$

Linear momentum $=mv=9.1\times {10}^{-31}\times 2.2\times {10}^6$
$=2.0\times {10}^{-24}kg-m/s$