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प्रश्न
Magnetic lines of force are closed continuous curves.
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उत्तर
True.
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संबंधित प्रश्न
Write any three properties of magnetic lines of force.
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?
Choose the correct option.
Inside a bar magnet, the magnetic field lines
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?
A closely wound solenoid of 800 turns and area of cross-section 2.5 × 10–4 m2 carries a current of 3.0 A. Explain the sense in which the solenoid acts like a bar magnet. What is its associated magnetic moment?
Which of the following statements about bar magnet is correct?
In which case of comparing solenoid and bar magnet there is no exact similarity?
Four point masses, each of value m, are placed at the comers of a square ABCD of side L, the moment of inertia of this system about an axis through A and parallel to BD is ______.
The magnetic moment of atomic neon is equal to
A magnetic needle suspended freely orients itself:-
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
A bar magnet of magnetic moment 3.0 Am is placed in a uniform magnetic field of 2 × 10-5T. If each pole of the magnet experience a force of 6 × 10-4 N, the length of the magnet is ______.
A toroid of n turns, mean radius R and cross-sectional radius a carries current I. It is placed on a horizontal table taken as x-y plane. Its magnetic moment m ______.
A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. (i) In which direction will it move? (ii) What will be the direction of it’s magnetic moment?
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?
Verify the Ampere’s law for magnetic field of a point dipole of dipole moment m = m`hatk`. Take C as the closed curve running clockwise along (i) the z-axis from z = a > 0 to z = R; (ii) along the quarter circle of radius R and centre at the origin, in the first quadrant of x-z plane; (iii) along the x-axis from x = R to x = a, and (iv) along the quarter circle of radius a and centre at the origin in the first quadrant of x-z plane.
A bar magnet is demagnetized by inserting it inside a solenoid of length 0.2 m, 100 turns, and carrying a current of 5.2 A. The coercivity of the bar magnet is ______.
