Let B′ is the new position of B,
Given that AB′ makes an angle 60∘ with the positive direction of X-axis.
A=(1,0), AB=r=2, θ=60∘
Now,
B′=(x1+rcosθ,y1+rsinθ)⇒B′=(1+2×cos60∘,0+2×sin60∘)
⇒B′=(1+2×12,0+2×√32)⇒B′=(2,√3)
So, the distance of B′ from origin
=√(2)2+(√3)2=√7 units
∴k2=7