Two vertical poles of heights, 20 m and 80 m stand a part on a horizontal plane. The height (in meters) of the point of intersection of the lines joining the top of each pole to the foot of the other, from this horizontal plane is :

The height of a right circular cylinder of maximum volume inscribed in a sphere of radius 3 is

A circuit connected to an ac source of emf e = e₀sin(100t) with t in seconds, gives a phase difference of $$\pi $$/4 between the emf e and current i. Which of the following circuits will exhibit this ?

Two very long, straight, and insulated wires are kept at 90° angle from each other in xy-plane as shown in the figure. These wires carry currents of equal magnitude I, whose directions are shown in the figure. The net magnetic field at point P will be :