In the following hexagons made up of two different `P` and `Q` current enters and leaves from points `X` and `Y` respectively In which case the magnetic field at its centre is not zero .

Current flows through uniform square frames as shown. In which case is the magnetic field at the centre of the frame not zero ?

Current flows through uniform square frames as shown. In which case is the magnetic field at the centre of the frame not zero ?

Current flows through uniform square frames as shown. In which case is the magnetic field at the centre of the frame not zero ?

Find the magnetic field at point P in following cases

An equilateal triangle is made by uniform wires AB, BC, CA. A current I enters at A and leaves from the mid point of BC. If the length of each side of the triangle is L, the magnetic field B at the centroid O of the triangle is

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.

Figures below show regular hexagons, with charges at the vertices. In which of the following cases the electric field at the centre is not zero

Figure below show regular hexagons with charges at the vertices. In which of the following cases the electric field at the centre is not zero