ICSE Class 10 Answered
Expert Answer
The figure below , the beam of electrons first passes between the poles N and S of a magnet producing the magnetic field in the plane of paper downwards. The magnetic field deflects the beam outwards perpendicular to the plane of paper.
Now the electron beam passes through the electric field acting in a direction perpendicular to the plane of paper outwards (i.e., the positive plate B is kept below the plane of paper and the negative plate A above it). The electric field will deflect the beam towards the positive plate i.e., inwards into the plane of paper. The strength of electric field is adjusted such that the deflection caused by the magnetic field is annulled by the deflection caused due to electric field, then the electron beam will pass undeflected.
Actually the two fields are made to act simultaneously in the same region. Only for convenience, they have been shown separately in the figure.
