Question

A student is measuring the effects of an electric circuit on a compass, and he is testing to see increasing the current will cause the compass needle to change direction faster. He does one trial using a 9-volt battery and another trial using a 1.5 volt battery. He takes accurate data. Based on good experimental design, which would improve his experiment?

A. he should use batteries of the same voltage but from different manufacturers to show he has used different variables.

B. He should add a nonworking Compass to act as a control.

C. He should repeat the test with three additional batteries of varying voltages to demonstrate the reproducibility of results.

D. He should use only one battery but do several trials using different circuit designs to ensure he is appropriate test groups.

( I think it's a or c)

Answer 1

The correct answer is C. More data - more precise is a dependency graph, illustrating how the electric current strength changes compass behavior.

Answer 2

Answer: option c

Change in electric current leads to change in electric field. This produces magnetic field. The compass responds to this magnetic field. To measure this and test, the student must try different batteries. With varying batteries, current produced would change and effect would be clearly visible. Hence, the result would be more accurate and precise.

The use of batteries of the same voltage but from different manufacturers would not result in much difference. Using one battery wont produce accurate data. we cannot generalize a result based on one reading.

Therefore, the student should repeat the test with three additional batteries of varying voltages to demonstrate the reproducible results.