Magnetic field strength at the centre of regular pentagon made of a conducting wire of uniform cross section area as shown in figure is:

The magnetic field at the centre O of the are shown in the figure is

the position vector of the centre of mass lt to r cm of an asymmetric uniform bar of negligible area of cross - section as shown in figure is :

the position vector of the centre of mass lt to r cm of an asymmetric uniform bar of negligible area of cross - section as shown in figure is :

The magnetic field strength at a point P distant r due to an infinite straight wire carrying a current i is as shown in the figure

The magnetic field strength at a point P distant r due to an infinite straight wire carrying a current i is as shown in the figure

A square loop of length L is made of wire of uniform cross-section carrying current l as shown in figure then magnetic field at centre of square is

Assertion : If a current is flowing through a conducting wire of non-uniform cross-section, drift speed and resistance both will increase at a section where cross-sectional area is less. Reason : Current density at such sections is more where cross-sectional area is less.

Assertion : If a current is flowing through a conducting wire of non-uniform cross-section, drift speed and resistance both will increase at a section where cross-sectional area is less. Reason : Current density at such sections is more where cross-sectional area is less.

A circular loop of radius 'r' of conducting wire connected with a Voltage source of zero internal resistance produces a magnetic field 'B' at its centre. If instead, a circular loop of radius '2r' made of same material, having the same cross section is connected to the same voltage source, what will be the magnetic field at its centre?