A current i is flowing in a straight conductor of length L. The magnetic induction at a point distant L/4 from its centre will be :
A long solenoid carrying a current produce’s a magnetic field B along its axis. If the current is doubled acid the number of turns per cm is halved, the new value of the magnetic field is :
The correct answer is: B
For paramagnetic materials magnetic susceptibility is related with temperature as :
For paramagnetic materials magnetic susceptibility is inversely proportional to the temperature i.e., proportional to T–1.
The correct answer is: ∝T-1
An electron and proton enter a uniform magnetic field perpendicular. Both have same kinetic energy. Which of the following is true?
When a charged particle enters a magnetic field perpendicularly, it moves on a circular path. The required centripetal force is provided by magnetic force.
i.e. magnetic force = Centripetal force.
Now kinetic energy of the particle
Therefore, Eq. (1) become
Hence trajectory of proton is less curved.
The correct answer is: Trajectory of proton is less curved
A charge of 10–6C is describing a circular path of radius 1cm making 5 revolution per second. The magnetic induction field at the centre of the circle is :
The correct answer is:
A charged particle enters a uniform magnetic field with velocity vector at an angle of 45° with the magnetic field. The pitch of the helical path followed by the particle is p. The radius of the helix will be :
The correct answer is:
A charged particle (charge q) is moving in a circle of radius R with uniform speed v. The associated magnetic moment µ is given by :
As revolving charge is equivalent to a current, so
where R is radius of circle and v is uniform speed of charged particle.
Now, magnetic moment associated with charged particle is given by
The magnetic induction at centre O in the following figure will be
A current carrying wire is bent in the L shape as shown in figure. The length of both arms extend to infinity. Then, the magnetic field at O is
A current loop consists of two identical semicircular parts each of radius R, one lying in the x - y plane and the other in x - z plane. If the current in the loop is i. The resultant magnetic field due to the two semiconductor parts at their common centre is :
The loop mentioned in the question must look like one as shown in the figure.
Magnetic field at the centre due to semicircular loop lying in x-y plane.
in negative z direction.
Similarly field due to loop in x-z plane, in negative y direction.
∴ Magnetic of resultant magnetic field,