Question

What is the value of q/m for a particle that moves in a circle of radius 6.6 mm in a 0.47 T magnetic field if a crossed 230 V/m electric field will make the path straight

Answer 1

Given:

Radius (r) = 6.6 mm = 6.6 × $10^{-3}$ m

Magnetic field (B) = 0.47 T

Electric field (E) = 230 V/m

To find:

Charge to mass ratio $\frac{q}{m}$

Solution:

As per motion EMF;

      E = v × B

• v = $\frac{E}{B}$ = $\frac{230}{0.47}$ ≈ 490 m/s

• r = $\frac{mv}{qB}$

• $\frac{q}{m}$ = $\frac{v}{r*B}$ =$\frac{490}{6.6*10^{-3}*0.47 }$

• Charge to mass ratio $\frac{q}{m}$ = 158 ×$10^{3}$ C/Kg