STUDY BOX ACADEMY – MAGNETISM NUMERICALS
1) Explain whether an alpha particle will experience any force in a magnetic field if :
(i) it is placed in the field at rest.
(ii) it moves in the magnetic field parallel to field lines.
(iii) it moves in the magnetic field perpendicular to field lines.
Sol (i) No, because, a charged particle at rest does not interact with the magnetic
field.
(ii) No, because, the force is zero if current and field are in the same direction.
(iii) Yes, because, the force is maximum when the current and magnetic field is
Y
maximum
M
2) A magnetic needle suspended freely- (a)
orients itself in a definite direction
(b)
DE
remains in any direction (c) become vertical with N-pole up (d) become vertical
with N-pole down
A
AC
3) A proton moving vertically downward enters a magnetic field pointing towards
north. In which direction proton will deflect?
X
BO
Ans Proton will represent the direction of current. So, the direction of current is
vertically downward. According to Fleming's left hand rule, if middle finger
Y
represents the direction of current and fore-finger represents the direction of
UD
magnetic field then thumb will represent the direction of Lorentz force acting on the
proton which deflects the proton in east direction.
ST
4) An electron moving vertically upward is deflected towards south by a uniform
magnetic field. Find the
directonof magnetic field
Ans east
5) determine the direction of force acting on the proton if the proton moves towards
the east by entering a un
iform magnetic field in downward direction
Ans It is given that the proton is moving towards the east, and therefore, the motion
of the current is towards the east. The direction of force is towards the north as the
1) Explain whether an alpha particle will experience any force in a magnetic field if :
(i) it is placed in the field at rest.
(ii) it moves in the magnetic field parallel to field lines.
(iii) it moves in the magnetic field perpendicular to field lines.
Sol (i) No, because, a charged particle at rest does not interact with the magnetic
field.
(ii) No, because, the force is zero if current and field are in the same direction.
(iii) Yes, because, the force is maximum when the current and magnetic field is
Y
maximum
M
2) A magnetic needle suspended freely- (a)
orients itself in a definite direction
(b)
DE
remains in any direction (c) become vertical with N-pole up (d) become vertical
with N-pole down
A
AC
3) A proton moving vertically downward enters a magnetic field pointing towards
north. In which direction proton will deflect?
X
BO
Ans Proton will represent the direction of current. So, the direction of current is
vertically downward. According to Fleming's left hand rule, if middle finger
Y
represents the direction of current and fore-finger represents the direction of
UD
magnetic field then thumb will represent the direction of Lorentz force acting on the
proton which deflects the proton in east direction.
ST
4) An electron moving vertically upward is deflected towards south by a uniform
magnetic field. Find the
directonof magnetic field
Ans east
5) determine the direction of force acting on the proton if the proton moves towards
the east by entering a un
iform magnetic field in downward direction
Ans It is given that the proton is moving towards the east, and therefore, the motion
of the current is towards the east. The direction of force is towards the north as the
