Gabriel used an iron nail to build an electromagnet (like the one seen below) that will pick up 4 paper clips. He has tried many changes to increase the strength of his electromagnet so that it will pick up 10 paper clips? For each of the following changes, predict and explain the most likely outcome for 2 points each:

Replacing the iron bolt with a plastic rod
Increasing the number of coils in the copper wire
Increasing the size of the battery

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.