A wire carries a current of 11.4 A in a direction that makes an angle of 11.4° with a magnetic field of magnitude 11.4 à 10-3 T. The magnitude of the force on 11.4 cm of this wire is:.a) 11.4 * 10^-3 N b) 0.130 N
c) 1.48 * 10^-2 N
d) 2.93 * 10^-3 N

(d) 2.93 x 10⁻³ N

Explanation:

Given;

current in the wire, I = 11.4 A

angle of inclination, θ = 11.4⁰

magnetic field on the wire, B = 11. 4  x 10⁻³

length of the wire, L = 11.4 cm = 0.114 m

The magnitude of magnetic force on the wire is given by;

F = BILsinθ

F = (11.4 x 10⁻³)(11.4)(0.114)(sin 11.4°)

F = 0.00293 N

F = 2.93 x 10⁻³ N

Therefore, the correct option is "D"

1732.05 J

Explanation:

The man is doing 100N of force on the rope at an angle of 30° where he is pulling a box 20 meters across the floor.

Work is equal to the force exerted in the direction of motion multiplied by the distance.

Mathematically, Work=F×D×CosineФ

where F=force in newtons

D=displacement in meters

Ф=the angle between the force vector and the direction of motion

Substitute values in formula

Work=100×20×cosine 30°

Work=100×20×0.86602540378

Work=1732.05 J