A long straight vertical wire carries a current of 10 ampere flowing upwards through it at a place where the horizontal component of the earth’s magnetic induction is 0.3 gauss. Then the total magnetic induction at a point 5 cm due north of the wire is

magnetic field due to the straight conductorB=μ0I2πR=2×10-7×105×10-2=4×10-5=0.4 gaussits direction will be towards west on the north side of wire.earth magnetic field at any point is towards north hence they are perpendicular net magnetic field  0.32+0.42= 0.5 G