Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Magnetics question

2022 · 29 Jul · Shift 1 · Q74
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Physics
  4. /Magnetics
  5. /2022 · 29 Jul · Shift 1 · Q74

Magnetics question

2022 · 29 Jul · Shift 1 · Q74

JEE MainPhysicsMagneticsNumerical+4 / −1
A wire of length 314 cm314 \mathrm{~cm}314 cm carrying current of 14 A14 \mathrm{~A}14 A is bent to form a circle. The magnetic moment of the coil is ‾\underline{\hspace{2cm}}​ A −m2-\mathrm{m}^{2}−m2. [Given π=3.14\pi=3.14π=3.14]
Numerical answer
View written solutionFree

Correct answer: 11

  1. Given data

    • Length of wire: 314 cm=3.14 m314\text{ cm} = 3.14\text{ m}314 cm=3.14 m
    • Current: I=14 AI = 14\text{ A}I=14 A
    • The wire is bent into a circle.
  2. Find the radius of the circle The length of the wire becomes the circumference: 2πr=3.142\pi r = 3.142πr=3.14 Using π=3.14\pi = 3.14π=3.14, 2(3.14)r=3.142(3.14)r = 3.142(3.14)r=3.14 6.28r=3.146.28r = 3.146.28r=3.14 r=3.146.28=0.5 mr = \frac{3.14}{6.28} = 0.5\text{ m}r=6.283.14​=0.5 m

  3. Find the area of the circular loop A=πr2A = \pi r^2A=πr2 A=3.14×(0.5)2A = 3.14 \times (0.5)^2A=3.14×(0.5)2 A=3.14×0.25=0.785 m2A = 3.14 \times 0.25 = 0.785\text{ m}^2A=3.14×0.25=0.785 m2

  4. Magnetic moment of the coil For a single circular loop, m=IAm = IAm=IA m=14×0.785m = 14 \times 0.785m=14×0.785 m=10.99 A-m2m = 10.99 \text{ A-m}^2m=10.99 A-m2

  5. Integer answer m≈11 A-m2m \approx 11 \text{ A-m}^2m≈11 A-m2

Therefore, the required integer answer is 11.

PreviousNext

More from Magnetics

  • A wire X of length 50 cm carrying a current of 2 A is placed parallel to a long wire Y of length 5 m. The wire Y carries a current of 3 A. The distance between two wires… Includes diagram2022 · MCQ
  • A charge particle moves along circular path in a uniform magnetic field in a cyclotron. The kinetic energy of the charge particle increases to 4 times its initial value. What will be the ratio of new radius to the original radius of…2022 · MCQ
  • Two long current carrying conductors are placed to each other at a distance of 8 cm between them. The magnitude of magnetic field produced at mid-point between the two conductors due to current flowing in them is 300 μ T. The equal…2022 · MCQ
  • Given below are two statements : Statement I : The electric force changes the speed of the charged particle and hence changes its kinetic energy; whereas the magnetic force does not change the kinetic energy of the charged particle.…2022 · MCQ
  • A coil of n number of turns wound tightly in the form of a spiral with inner and outer radii r1 and r2 respectively. When a current of strength I is passed through the coil, the magnetic field at its centre will be :2022 · MCQ
  • There are two infinitely long straight current carrying conductors and they are held at right angles to each other so that their common ends meet at the origin as shown in the figure given below. The ratio of current in both conductor is 1… Includes diagram2021 · MCQ
  • A charge Q is moving dl distance in the magnetic field B. Find the value of work done by B.2021 · MCQ
  • A solenoid of 1000 turns per metre has a core with relative permeability 500. Insulated windings of the solenoid carry an electric current of 5A. The magnetic flux density produced by the solenoid is : (permeability of free space = 4 π×…2021 · MCQ