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Soft iron is used to make the core of the transformer because of its ______. - Physics

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प्रश्न

Soft iron is used to make the core of the transformer because of its ______.

पर्याय

  • Low coercivity and low retentivity

  • Low coercivity and high retentivity

  • High coercivity and high retentivity

  • High coercivity and low retentivity

MCQ
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उत्तर

Soft iron is used to make the core of the transformer because of its Low coercivity and low retentivity.

Explanation:

Soft iron is used to make the core of transformers because of its high permeability. This enables complete magnetic flux coupling from the main coil to the secondary coil, and it possesses low retentivity and low coercivity.

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पाठ 11: Magnetic Materials - Exercises [पृष्ठ २६३]

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बालभारती Physics [English] Standard 12 Maharashtra State Board
पाठ 11 Magnetic Materials
Exercises | Q 1.2 | पृष्ठ २६३

संबंधित प्रश्‍न

State two advantages of an electromagnet over a permanent magnet.


What are permanent magnets? Give one example ?


Why should the material used for making permanent magnets have high coercivity?


Can we have a single north pole, or a single south pole?


Compare the direction of the magnetic field inside a solenoid with that of the field there if the solenoid is replaced by its equivalent combination of north pole and south pole.


The force on a north pole, `vecF = mvecB` , parallel to the field `vecB` . Does it contradict our earlier knowledge that a magnetic field can exert forces only perpendicular to itself?


Magnetic scalar potential is defined as `U(vec r_2) - U(vec r_1) = - ∫_vec(r_1)^vec(r_2)` `vec (B) . dvec(l)`

Apply this equation to a closed curve enclosing a long straight wire. The RHS of the above equation is then `-u_0 i` by Ampere's law. We see that `U(vec(r_2)) ≠ U(vec(r_1))` even when `vec r_2 =vec r_1` .Can we have a magnetic scalar potential in this case?


Which of the following four graphs may best represent the current-deflection relation in a tangent galvanometer?


To measure the magnetic moment of a bar magnet, one may use

(a) a tangent galvanometer
(b) a deflection galvanometer if the earth's horizontal field is known
(c) an oscillation magnetometer if the earth's horizontal field is known
(d) both deflection and oscillation magnetometer if the earth's horizontal field is not known


A uniform magnetic field of `0.20 xx 10^-3  "T"`  exists in the space. Find the change in the magnetic scalar potential as one moves through 50 cm along the field.


Figure shows some of the equipotential surfaces of the magnetic scalar potential. Find the magnetic field B at a point in the region.


The magnetic field at a point, 10 cm away from a magnetic dipole, is found to be `2.0 xx 10^-4  "T"` . Find the magnetic moment of the dipole if the point is (a) in end-on position of the dipole and (b) in broadside-on position of the dipole.


Show that the magnetic field at a point due to a magnetic dipole is perpendicular to the magnetic axis if the line joining the point with the centre of the dipole makes an angle of `tan^-1(sqrt 2)` with the magnetic axis


A bar magnet has a length of 8 cm. The magnetic field at a point at a distance 3 cm from the centre in the broadside-on position is found to be `4 xx 10^-6  "T"`.Find the pole strength of the magnet.


A magnetic dipole of magnetic moment `1.44  "A m"^2`is placed horizontally with the north pole pointing towards north. Find the position of the neutral point if the horizontal component of the earth's magnetic field is 18 μT.


Why is it not possible to make permanent magnets from paramagnetic materials?


The magnetic moment of the assumed dipole at the earth's centre is 8.0 × 1022 A m2. Calculate the magnetic field B at the geomagnetic poles of the earth. Radius of the earth is 6400 km.


The magnetic field due to the earth has a horizontal component of 26 μT at a place where the dip is 60°. Find the vertical component and the magnitude of the field.


The needle of a dip circle shows an apparent dip of 45° in a particular position and 53° when the circle is rotated through 90°. Find the true dip.


A moving-coil galvanometer has a 50-turn coil of size 2 cm × 2 cm. It is suspended between the magnetic poles producing a magnetic field of 0.5 T. Find the torque on the coil due to the magnetic field when a current of 20 mA passes through it.


A short magnet produces a deflection of 37° in a deflection magnetometer in Tan-A position when placed at a separation of 10 cm from the needle. Find the ratio of the magnetic moment of the magnet to the earth's horizontal magnetic field.


A bar magnet makes 40 oscillations per minute in an oscillation magnetometer. An identical magnet is demagnetized completely and is placed over the magnet in the magnetometer. Find the time taken for 40 oscillations by this combination. Neglect any induced magnetism.


A short magnet makes 40 oscillations per minute when used in an oscillation magnetometer at a place where the earth's horizontal magnetic field is 25 μT. Another short magnet of magnetic moment 1.6 A m2 is placed 20 cm east of the oscillating magnet. Find the new frequency of oscillation if the magnet has its north pole (a) towards north and (b) towards south.


Answer in brief.

Explain one application of electromagnet.


A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from ______.


In a permanent magnet at room temperature ______.


Which of the following is the most suitable material for making permanent magnet?

A steel wire of length 1 has a magnetic moment m it is then bent into a semicircular arc. The new magnetic moment is


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