Answer:

Explanation:
Given that:
- magnetic field intensity,

- kinetic energy of electron,

- we have mass of electron,

<em>Now, form the mathematical expression of Kinetic Energy:</em>




<u>from the relation of magnetic and centripetal forces we have the radius as:</u>



In 2Cr2O7 there’s 2 items; Cr and O
A) 1973 I believe it had something to do with the Arab wars happening at the time