Question

Can you show all the steps and explain questions 10, 11 and 12 please? The answers circled are probably wrong

10. Two long, straight parallel wires J and K are perpendicular to the page. The point P is equidistant from each wire as shown. A set of marked arrows "A" through "E" is shown. The wires have equal currents, directed out of J the page. The direction of the magnetic field at P is closest to the direction of which of the marked arrows? 11. Each of two long straight parallel wires, separated by a distance of 16 cm, carries a current of 20 A in the same direction. What is the magnitude of the net magnetic field at a point that is 10 cm from each wire? 10 em 10 cm straight wire O20A A) 40 HT B) 48 pT C) 57 ?T D) 64 HT 20A ( 16 cm F,= 20 (0.16) ( 12. The figure shows a cross section of three parallel wires each carrying a current of 15 A. The currents in wires A and C are out of the paper, while that in wire B is into the paper. If the distance R - 5.0 mm, what is the magnitude of the force on a 4.0-m length of wire C? 5 omm A) 18 mN B) 30 mN O 36 mN D) 54 mN E) 90 mN O,oo5

Answer 1

From right hand rule, the outward current at J produce North-west field. The outward current at K produce South-west field. The vertical components are cancelled each other and only horizontal components remains. The horizontal component is along west direction. That is the magnetic field at P shows the arrow E The current through each conductor i,-i 20 A Distance between the conductors r 0.16 m In-between the conductors Magnetic So at x= 10 cm from 4 and r-x from 12 fields are opposite directions in between the conductors 47x10 20 2n (0.16-0.1 0.1 20 = 26.67 × 10-6 T Outside the conductors Magnetic So at x= 10 cm from 4 and r+x from 12 fields are opposite directions in between the conductors 20 2n (0.16-0.1 0.1 4π × 10 20 = 106.67×10-6 T The magnitude magnetic field is B = 1 06.67 × 10-6-26.67x 1 O-5 -80x104 =80LT

(12) Given data The current is I-15 A Magnetic Force is F-ILB sin θ Magnetic Field is B- M Magnetic field by wire B Magnetic field by wire A 0-90 in both Force by wire B F 15x4 Force by wire C F 15x415 Both forces are acting in same direction: 10x15 4o x15 4TR 4o x15 1800x10 900x10 900x10 R- 5x103 900x10-7 e510 -18x103 -18 mN