1) Two short bar magnets of length 1cm each have magnetic moments 1.20 Am2 and 1.00 Am2 respectively. They are placed on a horizontal table parallel to each other with their N poles pointing towards the south. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the midpoint O of the line joining their centre s is close to (Horizontal component of the earth's magnetic induction is 3.6 x 10-5 Wb/m2) A) $3.6\times 10^{-5} Wb/m^{2}$ B) $2.56\times 10^{-4} Wb/m^{2}$ C) $3.50\times 10^{-4} Wb/m^{2}$ D) $5.80\times 10^{-4} Wb/m^{2}$ Answer: Option BExplanation:Bnet = B1+B2 +BH $B_{net}=\frac{\mu_{0}}{4\pi}\frac{(M_{1}+M_{2})}{r^{3}}+B_{H}$ $=\frac{10^{-7}(1.2+1)}{(0.1)^{3}}+3.6\times 10^{-5}$ = $2.56\times 10^{-4} Wb/m^{2}$
