Two concentric coils, of turns each are placed in the same plane. Their radii are $20 \mathrm{cm}$ and $40 \mathrm{cm}$ and carry and current respectively in opposite directions. The magnetic induction (in Tesla) at their centre is
Important Questions on Magnetic Effect of Electric Current
The ratio of magnetic field and magnetic moment at the centre of a current-carrying circular loop is . When both the current and radius is doubled then the ratio will be
A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is . It is then bent into a circular coil of n turns. The magnetic field at the centre of this coil of turns will be
A length $L$ of wire carries a steady current . It is bent first to form a circular plane coil of one turn. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the centre caused by the same current is
When a certain length of wire is turned into one circular loop, the magnetic induction at the centre of coil due to some current flowing is . If the same wire is turned into three loops to make a circular coil, the magnetic induction at the centre of this coil for the same current will be
The circular loop of a wire and a long straight wire carries currents and respectively as shown in the figure. Assuming that these are placed in the same plane, the magnetic fields will be zero at the centre of the loop when the separation is
An electron moving in a circular orbit of radius makes rotations per second. The magnetic field produced at the center has a magnitude,
A particle carrying a charge equal to times the charge on an electron is rotating per second in a circular path of radius. The value of the magnetic field produced at the centre will be )
A helium nucleus makes a full rotation in a circle of radius in two seconds. The value of the magnetic field at the centre of the circle will be
