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Use Lenz’s law to determine the direction of induced current in the situation described by the figure: A wire of irregular shape turning into a circular shape. - Physics

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प्रश्न

Use Lenz’s law to determine the direction of induced current in the situation described by the figure:

A wire of irregular shape turning into a circular shape.

थोडक्यात उत्तर
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उत्तर

According to Lenz’s law, the direction of the induced emf is such that it tends to produce a current that opposes the change in the magnetic flux that produced it.

A greater area and, by extension, a stronger magnetic flux, are the results of a change in shape. In order to create opposing flux, Lenz's law is used to build up an induced current in the circular wire in an anticlockwise direction. Thus, the upward-directed magnetic field is a result of it.

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पाठ 6: Electromagnetic Induction - EXERCISES [पृष्ठ १७५]

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एनसीईआरटी Physics [English] Class 12
पाठ 6 Electromagnetic Induction
EXERCISES | Q 6.2 (a) | पृष्ठ १७५

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

State Lenz's law. Illustrate, by giving an example, how this law helps in predicting the direction of the current in a loop in the presence of a changing magnetic flux.


Describe a simple experiment (or activity) to show that the polarity of emf induced in a coil is always such that it tends to produce a current which opposes the change of magnetic flux that produces it.


Predict the directions of induced currents in metal rings 1 and 2 lying in the same plane where current I in the wire is increasing steadily.


Predict the direction of induced current in a metal ring when the ring is moved towards a straight conductor with constant speed v. The conductor is carrying current I in the direction shown in the figure.


A short magnet is moved along the axis of a conducting loop. Show that the loop repels the magnet if the magnet is approaching the loop and attracts the magnet if it is going away from the loop.


A pivoted aluminium bar falls much more slowly through a small region containing a magnetic field than a similar bar of an insulating material. Explain.


Explain, with the help of a suitable example, how we can show that Lenz's law is a consequence of the principle of conservation of energy.


Lenz’s law is a consequence of the law of conservation of ______.


The polarity of induced emf is given by ______.

2 A 40 kg boy whose legs are 4 cm in area and 50 cm long falls through a height of 2 m without breaking his leg bones. If the bones can withstand stress of 0.9 x 108 N/m2. The Young's modulus for the material of the bone is ______.


Young's modulus for aluminium is 7 × 1010 Pa. The force needed to stretch an aluminium wire of diameter 2 mm and length 800 mm by 1 mm is ______.


A bar magnet is dropped through a copper ring acceleration of magnet is


For a coil having L = 2 mH, current flows at the rate of 10-3 AIS. The e.m.f induced is


There are two coils A and B as shown in figure. A current starts flowing in B as shown, when A is moved towards B and stops when A stops moving. The current in A is counterclockwise. B is kept stationary when A moves. We can infer that ______.


A wire in the form of a tightly wound solenoid is connected to a DC source, and carries a current. If the coil is stretched so that there are gaps between successive elements of the spiral coil, will the current increase or decrease? Explain.


Consider a metal ring kept (supported by a cardboard) on top of a fixed solenoid carrying a current I (Figure). The centre of the ring coincides with the axis of the solenoid. If the current in the solenoid is switched off, what will happen to the ring?


A conducting wire XY of mass m and neglibile resistance slides smoothly on two parallel conducting wires as shown in figure. The closed circuit has a resistance R due to AC. AB and CD are perfect conductors. There is a ˆ. magnetic field `B = B(t)hatk`.

  1. Write down equation for the acceleration of the wire XY.
  2. If B is independent of time, obtain v(t) , assuming v(0) = u0.
  3. For (b), show that the decrease in kinetic energy of XY equals the heat lost in R.

A metallic ring of mass m and radius `l` (ring being horizontal) is falling under gravity in a region having a magnetic field. If z is the vertical direction, the z-component of magnetic field is Bz = Bo (1 + λz). If R is the resistance of the ring and if the ring falls with a velocity v, find the energy lost in the resistance. If the ring has reached a constant velocity, use the conservation of energy to determine v in terms of m, B, λ and acceleration due to gravity g.


A long solenoid ‘S’ has ‘n’ turns per meter, with diameter ‘a’. At the centre of this coil we place a smaller coil of ‘N’ turns and diameter ‘b’ (where b < a). If the current in the solenoid increases linearly, with time, what is the induced emf appearing in the smaller coil. Plot graph showing nature of variation in emf, if current varies as a function of mt2 + C.


Use Lenz’s law to determine the direction of induced current in the situation described by the figure.

A circular loop being deformed into a narrow straight wire.


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