#### Two coaxial solenoids of different radii carry current I in the same direction. Let  be the magnetic force on the inner solenoid due to the outer one and   be the magnetic force on the outer solenoid due to the inner one. Then : Option 1)    =       =  0 Option 2)   is radially inwards and    radially outwards Option 3) is radially inwards and   = 0 Option 4) is radially  outwards  =  0

As we learnt in

Solenoid -

A cylinderical coil of many tightly wound turns of insulated wire generally diameter of the coil smaller than its length

- wherein

Option 1)

=       =  0

Correct Option

Option 2)

Incorrect Option

Option 3)

is radially inwards and   = 0

Incorrect Option

Option 4)

Incorrect Option