SAT Subject Physics Practice Question 477: Answer and Explanation
8. A student uses a magnetic compass to perform a laboratory experiment in the Northern Hemisphere. She then carries the same magnetic compass with her to the Southern Hemisphere, taking care not to damage the compass in any way. When she reaches her destination at the equivalent latitude and longitude in the Southern Hemisphere, she prepares to perform the same laboratory experiment. The student looks at the compass before performing the experiment to see if the compass needle has changed. How has the compass changed?
A. The compass needle points 90°to the left of the expected direction.
B. The compass needle points 90°to the right of the expected direction.
C. The compass needle slowly rotates in a counter-clockwise direction.
D. The compass needle slowly rotates in a clockwise direction.
E. There has been no change in the compass.
Correct Answer: E
The correct answer is (E). The compass is unaffected by the change from the Northern Hemisphere to the Southern Hemisphere. It will work in the same manner all over the world. The magnetic needle points toward the Magnetic North Pole in the Northern Hemisphere.