A fine pencil of `beta`-particles, moving with a speed v, enters a region (region I), where a
Channel: Doubtnut
Date: 2020-08-02

A fine pencil of `beta`-particles, moving with a speed v, enters a region (region I), where a uniform electric field and a uniform magnetic field are both present. These `beta`-particles then move into region II where only the magnetic field, (out of the two fields present in region I) exists. The path of the `beta`-particles, in the two regions is as shown in the figure.   (i) state the direction of magnetic field.  (ii) state the relation between E and B in region I.  (iii) Drive the expression for the radius of the circular path of the `beta`-particle in region II.  (iv) If the magnitude of magnetic field, in region II is changed to n times its earlier value, (without changing the magnetic field in region I) find the factor by which the radius of this circular path would change.