Advertisements
Advertisements
प्रश्न
A closely wound solenoid of 2000 turns and area of cross-section 1.6 × 10–4 m2, carrying a current of 4.0 A, is suspended through its centre allowing it to turn in a horizontal plane.
- What is the magnetic moment associated with the solenoid?
- What is the force and torque on the solenoid if a uniform horizontal magnetic field of 7.5 × 10–2 T is set up at an angle of 30° with the axis of the solenoid?
Advertisements
उत्तर
Number of turns on the solenoid, n = 2000
Area of cross-section of the solenoid, A = 1.6 × 10−4 m2
Current in the solenoid, I = 4 A
- The magnetic moment along the axis of the solenoid is calculated as:
M = nAI
= 2000 × 1.6 × 10−4 × 4
= 1.28 Am2 - Magnetic field, B = 7.5 × 10−2 T
Angle between the magnetic field and the axis of the solenoid, θ = 30°
Torque, τ = MB sin θ
= 1.28 × 7.5 × 10−2 × sin 30°
= 4.8 × 10−2 Nm
Since the magnetic field is uniform, the force on the solenoid is zero.
The torque on the solenoid is 4.8 × 10−2 Nm.
APPEARS IN
संबंधित प्रश्न
How are the magnetic field lines different from the electrostatic field lines?
Predict the polarity of the capacitor in the situation described below :
An iron needle is attracted to the ends of a bar magnet but not to the middle region of the magnet. Is the material making up the ends of a bare magnet different from that of the middle region?
Two bar magnets are placed close to each other with their opposite poles facing each other. In absence of other forces, the magnets are pulled towards each other and their kinetic energy increases. Does it contradict our earlier knowledge that magnetic forces cannot do any work and hence cannot increase kinetic energy of a system?
Answer the following question.
Write the four important properties of the magnetic field lines due to a bar magnet.
Solve the following problem.
A magnetic pole of a bar magnet with a pole strength of 100 A m is 20 cm away from the centre of a bar magnet. The bar magnet has a pole strength of 200 A m and has a length of 5 cm. If the magnetic pole is on the axis of the bar magnet, find the force on the magnetic pole.
A short bar magnet placed with its axis at 30° with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to 4.5 × 10–2 J. What is the magnitude of magnetic moment of the magnet?
If the bar magnet is turned around by 180°, where will the new null points be located?
Which of the following statements about bar magnet is correct?
When iron filings are sprinkled on a sheet of glass placed over a short bar magnet then, the iron filings form a pattern suggesting that the magnet has ______.
Magnetic field at far axial point due to solenoid as well as bar magnet varies ______.
According to the dipole analogy 1/ε0 corresponds to ______.
When a current is passed through a tangent galvanometer, it gives a deflection of 30° for 60° correction, the current must be
A particle having charge 100 times that of an electron is revolving in a circular path by radius 0.8 with one rotation per second. The magnetic field produced at the centre is
Suppose we want to verify the analogy between electrostatic and magnetostatic by an explicit experiment. Consider the motion of (i) electric dipole p in an electrostatic field E and (ii) magnetic dipole m in a magnetic field B. Write down a set of conditions on E, B, p, m so that the two motions are verified to be identical. (Assume identical initial conditions.)
A bar magnet of magnetic moment m and moment of inertia I (about centre, perpendicular to length) is cut into two equal pieces, perpendicular to length. Let T be the period of oscillations of the original magnet about an axis through the midpoint, perpendicular to length, in a magnetic field B. What would be the similar period T′ for each piece?
A long straight wire of circular cross section of radius 'a' carries a steady current I. The current is uniformly distributed across its cross section. The ratio of magnitudes of the magnetic field at a point `a/2` above the surface of wire to that of a point `a/2` below its surface is ______.
