A bar magnet of magnetic moment Mis placed at a distance D with its axis along positive X-axis. Likewise, second bar manget of magnetic moment M is placed at a distance 2D on positive Y-axis and perpendicular to it as shown in the figure. The magnitude of magnetic field at the origin  is `|B|=alpha[(eta_(0))/(4pi)(M)/(D^(3))]`. The value of a must be (assume `D gt gt l`, where l is the length of magnets)
 

Two identical bar magnets of magnetic moment M each, are placed along X and Y-axes, respectively at a distance d from the origin (as shown in the figure). The origin lies on perpendicular bisector of magnet placed on X-axis and on the magnetic axis of magnet placed on Y-axis If the magnitude of total magnetic field at the origin is B = alpha[(mu_(0))/(4pi) (M)/(d^(3))] then the value of constant alpha will be ( d gt gt l. where lis the lenght of the bar magnets and direction of N to S in magnets is oppsite with respect to each other)

Two identical short bar magnets of magnetic moment M each are placed at distance r apart in end-on position, then magnetic force between both is

A bar magnet of length ! and magnetic dipole moment M is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be

Two identical bar magnets, each of magnetic moment M, are placed as shown in figure. Magnetic field at point