Advertisements
Advertisements
Question
A rigid wire consists of a semi-circular portion of radius R and two straight sections (figure). The wire is partially immersed in a perpendicular magnetic field B, as shown in the figure. Find the magnetic force on the wire if it carries a current i.
Advertisements
Solution
Given:-
Radius of the semi-circular portion of the rigid wire = R
Magnetic field = B
Electric current flowing through the wire = i
As per the question, the wire is partially immersed in a perpendicular magnetic field.
As PQ and RS are straight wires of length l each and strength of the magnetic field is also same on both the wires, the force acting on these wires will be equal in magnitude but their directions will be opposite to each other.(Direction of force can be found out using Fleming's left hand rule.)
So, the magnetic force on the wire PQ and the force on the wire RS are equal and opposite to each other. Both the forces cancel each other.
Therefore, only the semicircular loop PR will experience a net magnetic force.
Here, angle between the length of the wire and magnetic field, θ = 90˚
Magnetic force in the loop PR,
`vecF = iveclxxvecB`
Here, l = 2R
`vecF=i2R xx vecB`
`vecF = i2RB sin90^circ`
APPEARS IN
RELATED QUESTIONS
Sketch the change in flux, emf and force when a conducting rod PQ of resistance R and length l moves freely to and fro between A and C with speed v on a rectangular conductor placed in uniform magnetic field as shown in the figure
A current of 5.0 A exists in the circuit shown in the figure. The wire PQ has a length of 50 cm and the magnetic field in which it is immersed has a magnitude of 0.20 T. Find the magnetic force acting on the wire PQ.
Consider a non-conducting plate of radius r and mass m that has a charge q distributed uniformly over it. The plate is rotated about its axis with an angular speed ω. Show that the magnetic moment µ and the angular momentum l of the plate are related as `mu = q/(2 m)l`
Consider a solid sphere of radius r and mass m that has a charge q distributed uniformly over its volume. The sphere is rotated about its diameter with an angular speed ω. Show that the magnetic moment µ and the angular momentum l of the sphere are related as `mu = q/(2m) l`
Consider a straight piece of length x of a wire carrying a current i. Let P be a point on the perpendicular bisector of the piece, situated at a distance d from its middle point. Show that for d >> x, the magnetic field at P varies as 1/d2 whereas for d << x, it varies as 1/d.
A long wire carrying a current i is bent to form a place along α . Find the magnetic field B at a point on the bisector of this angle situated at a distance x from the vertex.
Consider the situation shown in the figure. Suppose the circular loop lies in a vertical plane. The rod has a mass m. The rod and the loop have negligible resistances but the wire connecting O and C has a resistance R. The rod is made to rotate with a uniform angular velocity ω in the clockwise direction by applying a force at the midpoint of OA in a direction perpendicular to it. Find the magnitude of this force when the rod makes an angle θ with the vertical.
In the circuit shown in the figure, find the value of the current shown in the ammeter A.
Two infinitely long current carrying conductors X and Y are kept parallel to each other, 24 cm apart in a vacuum. They carry currents of 5A and 7A respectively, in the same direction, as shown in the figure below. Find the position of a neutral point, i.e., a point where resultant magnetic flux density is zero. (Ignore earth’s magnetic field).
A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires.
(a) What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero?
(b) What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field same as before?
(Ignore the mass of the wires) g = 9.8 m s–2.
Correct expression for force on a current carrying conductor of length dl in a magnetic field is ______.
When a magnetic compass needle is carried nearby to a straight wire carrying current, then
- the straight wire cause a noticeable deflection in the compass needle.
- the alignment of the needle is tangential to an imaginary circle with straight wire as its centre and has a plane perpendicular to the wire.
A charged particle is moving on circular path with velocity v in a uniform magnetic field B, if the velocity of the charged particle is doubled and strength of magnetic field is halved, then radius becomes ______.
A small object with charge q and weight mg is attached to one end of a string of length ‘L’ attached to a stationary support. The system is placed in a uniform horizontal electric field ‘E’, as shown in the accompanying figure. In the presence of the field, the string makes a constant angle θ with the vertical. The sign and magnitude of q ______.
A current of 3 A is flowing in a linear conductor having a length of 40 cm. The conductor is placed in a magnetic field of strength of 500 gauss and makes an angle of 30° with the direction of the field. It experiences a force of magnitude:
A straight conductor of length 2m moves at a speed of 20 m/s. When the conductor makes an angle of 30° with the direction of magnetic field of induction of 0.1 wbm2 then induced emf:
