A long straight wire carries a current of 40 A in a region where a uniform external magnetic field has a 30-?T magnitude and is parallel to the current. What is the magnitude of the resultant magnetic field at a point that is 20 cm from the wire?
A. 70 ?T
B. 40 ?T
C. 10 ?T
D. 50 ?T
E. 36 ?T
Answer: D
You might also like to view...
Which of the following is not a characteristic of the stars of the disk component of our galaxy?
a. circular orbits b. randomly inclined orbits c. higher metal abundance d. young stars e. star formation regions
In absolute visual magnitude, Mv, the subscript V refers to the:
A) apparent magnitude of a star observed from Earth. B) wavelengths of light your eye can see. C) distance between the sources of light. D) luminosity of a star observed from Earth.
Coulomb's Law: A point charge Q = -12 ?C, and two other charges q2 and q2, are placed on x-y axes as shown in the figure. The electric force components on charge Q are Fx = +0.005 N and Fy = -0.003 N. (k = 1/4??0 = 9.0 × 109 N ? m2/C2, e = 1.6 × 10-19 .C(a) How many excess electrons are there in charge Q?(b) What are the charges q1 and q2, including their signs?
What will be an ideal response?
Each of the following is a prediction of the theory of relativity. Which one is crucial to understanding how the Sun provides light and heat to Earth?
A) If you observe someone moving by you, you'll see their time running slowly. B) Gravity is curvature of spacetime. C) E = mc2 D) Time runs slower on the surface of the Sun than on Earth. E) Space is different for different observers. Time is different for different observers. Spacetime is the same for everyone.