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Physics Question on Electromagnetic induction

A wire in the form of a circular loop of one turn carrying a current produces a magnetic field B at the centre. If the same wire is looped into a coil of two turns and carries the same current, the new value of magnetic induction at the centre is

A

4B

B

2B

C

3B

D

5B

Answer

4B

Explanation

Solution

A wire in the form of a circular loop of one turn carrying a current produces a magnetic field B at the centre. If the same wire is looped into a coil of two turns and carries the same current, the new value of magnetic induction at the centre is

The magnetic field at its center B = μ0I/2πr

Thus the length of the wire L = 2πr

But the same wire is looped into a coil of radius r2 of two turns

r2 = r/2

The magnetic field at its center B = (μ0I/2πr2) x n = [μ0I/2π(r/2)] x 2 = 4 x μ0I/2πr =4B

Bnew=n2B_{new} = n^2 B = (2)2^2 B = 4B

Magnetic field, also called a vector field, represents the magnetic influence on movingelectric charges, magnetic materials, andelectric currents. The magnetic fields force moving electrically charged particles in a circular or helical path and the charged particles experience a force perpendicular to their own velocity and to the magnetic field. Magnetic field can be expressed as the area around a magnet wherein the effect of magnetism is felt.

  • The symbol of the Magnetic Field can be denoted by B or H. It is denoted mathematically by quantities known as vectors which have direction and magnitude both.
  • Two different vectors help represent magnetic field: Magnetic flux density (or magnetic induction) and Magnetic field strength (or magnetic field intensity) each symbolized by B and _H _respectively.
  • The unit of Magnetic Field is Telsa and its base unit is (Newton.Second)/Coulomb.
  • Magnetic field lines are known to not cross one another. In fact, magnetic lines form closed loops, beginning from the north pole and ending at the south pole.
  • The density of the field lines generally indicates the strength of the field.

Discover more from this chapter:Electromagnetic Induction