The magnetic field at the centre of a circular coil of radius $r$ carrying current $I$ is ${B_1}$. The field at the centre of another coil of radius $2 r$ carrying same current $I$ is ${B_2}$. The ratio $\frac{{{B_1}}}{{{B_2}}}$ is
$0.5$
$1$
$2$
$4$
Give definition of $1\, \mathrm{T}$ magnetic field.
When equal current is passed through two coils, equal magnetic field is produced at their centres. If the ratio of number of turns in the coils is $8: 15$, then the ratio of their radii will be
Which of the following statements regarding magnetic lines of force is correct?
Figure shows a square loop $ABCD$ with edge length $a$. The resistance of the wire $ABC$ is $r$ and that of $ADC$ is $2r$. The value of magnetic field at the centre of the loop assuming uniform wire is
A hollow cylinder having infinite length and carrying uniform current per unit length $\lambda$ along the circumference as shown. Magnetic field inside the cylinder is