Answer a:
A 1.5 V battery, the electromagnet picked up an average of 6 paper clips, while with the 6.0 V battery, an average of 23 paper clips were picked up. Battery of 6.0V is 6.0/1.5 = 4 times stronger than battery of 1.5 V
Answer b:
Ratio of the number of paper clips picked up using the 6.0 V battery to the number picked up using the 1.5 V battery is = 23/6 = 3.8 ≈ 4.
Answer c:
As the voltage power increase, more paper clips were picked up by electromagnet. This indicated that there is a direct relationship. Mathematically it can be expressed as:
Voltage Power α Number of paper clips that were picked up