Question
Two coaxial solenoids of different radius carry current $$I$$ in the same direction. $$\overrightarrow {{F_1}} $$ be the magnetic force on the inner solenoid due to the outer one and $$\overrightarrow {{F_2}} $$ be the magnetic force on the outer solenoid due to the inner one. Then :
A.
$$\overrightarrow {{F_1}} $$ is radially inwards and $$\overrightarrow {{F_2}} = 0$$
B.
$$\overrightarrow {{F_1}} $$ is radially outwards and $$\overrightarrow {{F_2}} = 0$$
C.
$$\overrightarrow {{F_1}} = \overrightarrow {{F_2}} = 0$$
D.
$$\overrightarrow {{F_1}} $$ is radially inwards and $$\overrightarrow {{F_2}} $$ is radially outwards
Answer :
$$\overrightarrow {{F_1}} = \overrightarrow {{F_2}} = 0$$
Solution :
$$\overrightarrow {{F_1}} = \overrightarrow {{F_2}} = 0$$
because of action and reaction pair