NEET Magnetic Field Due to Circular Current Carrying Wire MCQs & PYQs

An otherwise infinite, straight wire has two concentric loops of radii a and b carrying equal
currents in opposite directions as shown. The magnetic field at the common centre is zero for

A wire loop is formed by joining two sections of radii r1 and r2 subtending an angle θ at O. The magnetic field at O is B0.

A charge Q is uniformly distributed over the surface of non-conducting disc of radius R. The
disc rotates about an axis perpendicular to its plane and passing through its centre with an
angular velocity ω. As a result of this rotation a magnetic field of induction B is obtained at
the centre of the disc. If we keep both the amount of charge placed on the disc and its
angular velocity to be constant and vary the radius of the disc then the variation of the
magnetic induction at the centre of the disc will be represented by the figure

A current I is flowing through the loop. The direction of the current and the shape of the loop are as shown in the figure. The magnetic field at the centre of the loop is (MA = R, MB = 2R, angle DMA = 90°)

A coil having N turns is would tightly in the form of a spiral with inner and outer radii a and b respectively. When a current I passes through the coil, the magnetic field at its centre is :

A particle carrying a charge equal to 100 times the charge on an electron is rotating per second in a circular path of radius 0.8m. The value of the magnetic field produced at the centre will be : (μ0 = permeability constant)

The magnetic induction at the centre O of the current carrying bent wire shown in the adjoining figure is :

A cell is connected between the points A and C of a circular conductor ABCD with O as centre and angle AOC = 60°. If B1 and B2 are the magnitudes of the magnetic fields at O due to the currents in ABC and ADC respectively, then ratio B1/B2 is :-

Figure shows three cases, in all cases the circular part has radius r and stragiht ones are infinitely long. For the same current the ratio of field B at center P in the three cases B1 : B2 : B3 is :

Two very thin metallic wires placed along X and Y-axis carry equal currents as shown in figure. AB and CD are lines at 45º with the axes with origin of axes of O. The magnetic fields will be zero on the line :