A cell is connected between the points A and C of a circular conductor ABCD of centre `'O'.angle AOC = 60^(@)`. If` B_(​1) and B_(​2)` are the magnitudes of the magnetic fields at O due to the currents in ABC and ADC respectively, the ratio `(B_(1))/(B_(2))`, is

The magnitude of the magnetic filed B due to the loop ABCD at origin (O) is

The magnitude of the magnetic field (B) due to loop ABCD at the origin (O) is

The figure shows tow coaxial circulalr loop a1 and 2, which forms same solid angle theta at point O . If B_1 and B_2 are the magnetic fields produced at the point O due to loop 1 and 2 respectively, then

A magnetic compass needl oscillates 30 times per minute at a place where the dip is 45^(@) and 40 times per minute where the dip is 30^(@) if B_(1) and B_(2) are respectively the total magnetic field due to the earth at the two places then the ratio B_(1)//B_(2) is best given by

A cell is connected across two points P and Q of a uniform circular conductor, figure. Prove that the magnetic field at its centre O will be zero.

A and B are two concentric circular conductors of centre O and carrying currents i_(1) and i_(2) as shown in the adjacent figure. If ratio of their radii is 1:2 and ratio of the flux densities at O due to A and B is 1:3 , then the value of i_(1)//i_(2) is

As shown in figure a cell is connected across two points A and B of a uniform circular conductor of radius r. Prove that the magnetic field induction at its centre O will be zero.