Question

What is cyclotron frequency of an electron with an energy of 100 eV in the earth's magnetic field of $1\times {10}^{-4}weber/m^2$ if its velocity is perpendicular to magnetic field?

• A. 0.7 MHz
• B. 2.8 MHz
• C. 1.4 MHz
• D. 2.1 MHz

Answer 1

Answer: (B)

2.8 MHz

$Cyclotronfrequency=f=\frac{qB}{2\pi m}$
$f=\frac{100\times 1.6\times {10}^{-19}\times {10}^{-4}}{2\pi \times 9.1\times {10}^{-31}}$
$=2.8Mhz$