Q 14

A point charge Q moves on the x-axis in the positive direction with a speed of 280 m/s.A point P is on the y-axis at y = +70 mm.The magnetic field produced at the point P,as the charge moves through the origin,is equal to What is the charge Q? (μ_{0} = 4π × 10^{-7} T • m/A)
A) -53 μC
B) +53 μC
C) -39 μC
D) +39 μC
E) +26 μC

Q 15

A point charge Q moves on the x-axis in the positive direction with a speed of 370 m/s.A point P is on the y-axis at y = +80 mm.The magnetic field produced at point P,as the charge moves through the origin,is equal to When the charge is at x = +40 mm,what is the magnitude of the magnetic field at point P? (μ_{0} = 4π × 10^{-7} T • m/A)
A) 0.57 μT
B) 0.74 μT
C) 0.92 μT
D) 1.1 μT
E) 1.3 μT

Q 16

At what distance from the central axis of a long straight thin wire carrying a current of 5.0 A is the magnitude of the magnetic field due to the wire equal to the strength of the Earth's magnetic field of about 5.0 × 10^{-5} T? (μ_{0} = 4π × 10^{-7} T • m/A)
A) 1.0 cm
B) 2.0 cm
C) 3.0 cm
D) 4.0 cm
E) 5.0 cm