Question

A particular type of fundamental particle decays by transforming into an electron e- and a positron e (same amount of charge as e- but with positive sign). Suppose the decaying particle is at rest in a uniform magnetic field B of magnitude 3.53 mT and the e- and e move away from the decay point in paths lying in a plane perpendicular to B. How long after the decay do the e- and e collide

Answer 1

Answer:

Time after which it collide again is

$T = 1.01 \times 10^{-8} s$

Explanation:

As we know that the neutral particle decays into two particles i.e. electron and positron

As we know that both particles are of same mass but opposite charge

So both particles will revolve in the circle in opposite sense

So both particles will collide again after one complete revolution

So the time period of revolution is given as

$T = \frac{2\pi m}{qB}$

so we whave

$T = \frac{2\pi(9.1 \times 10^{-31})}{(1.6 \times 10^{-19})(3.53 \times 10^{-3})}$

$T = 1.01 \times 10^{-8} s$