At a distance of 5cm from axis point at which field is observed is P. At P, two perpendicular fields exists. B1 is magnetic field of solenoid and B2 is magnetic field of wire.
Now, B1=µ0nI1 =µ0(1000)×7×10−3=7µ0T And B2=
µ0I2
2πd
=
m0I2
2π×5×10−2
=
10µ0I2
π
T As, B1=Bcosθ and B2=Bsinθ ⇒tanθ=
B2
B1
⇒B2=B1tan60∘ (Given, θ=60∘ ) Substituting values of B2 and B1, we get