MagnetismHard
Question
A beam of cathode rays is accelerated by a potential V and then subjected to crossed electric (E) and magnetic field (B). such that the beam is not deflected. The specific charge of the cathode rays is given by ?
Options
A.
B.
C.
D.
Solution
When a beam of cathode rays (or electrons) are subjected to cross electric (E) and magnetic (B) fields, the beam is not defined, if
Force on electron due to magnetic field = Force on electron due to electric field
Bev = eE
or, v =
...... (i)
If V is the potential difference between the anode and the cathode, then
∴
mv2 = eV
...... (ii)
Substituting the value of v from equation (i) in equation (ii), we get
Specific charge of the cathode rays
Force on electron due to magnetic field = Force on electron due to electric field
Bev = eE
or, v =
...... (i) If V is the potential difference between the anode and the cathode, then
∴
mv2 = eV ...... (ii) Substituting the value of v from equation (i) in equation (ii), we get
Specific charge of the cathode rays
Create a free account to view solution
View Solution FreeMore Magnetism Questions
A magnetic neddle is kept in a non-uniform magnetic field. It may experience...A particle of mass M and positive charge Q, moving with a constant velocity , enters a region of uniform static magnetic...Current flows through uniform,square frames as shown. In which case is the magnetic field at the centre of the frame not...A uniform electric field and a uniform magnetic field are acting along the same direction ina certain region. If an elec...At a specific instant emission of radioactive compound is deflected in a magnetic field. The compound can emit (i) elect...