It is fairly easy to build an electromagnet. All you need to do is wrap some insulated copper wire around an iron core. If you attach a battery to the wire, an electric current will begin to flow and the iron core will become magnetized. When the battery is disconnected, the iron core will lose its magnetism. Follow these steps.
Step 1 - Gather the Materials
One iron nail fifteen centimeters (6 in) long
Three meters (10 ft) of 22 gauge insulated, stranded copper wire
One or more D-cell batteries
Step 2 - Remove some Insulation
Step 3 - Wrap the Wire Around the Nail
Step 4 - Connect the Battery
Answer:
none of above. The answer is celsius
Correct answer: a) True.
In fact, the soil at the poles consists mainly of snow. Snow has an albedo of 90%: albedo is the fraction of light (and so, of energy) that is reflected back to the space. This means that at the poles, about 90% of the light is reflected back to the space, while only 10% is absorbed.
Answer:
The question was incomplete. Here is the complete question.
Explanation:
A helium-filled balloon escapes a child’s hand at sea level and 20.0C. When it reaches an altitude of 3600 m, where the temperature is 5.0∘C and the pressure only 0.68 atm, how will its volume compare to that at sea level?
The ideal gas equation:

P = absolute pressure
V = Volume of a gas
n = no of moles of a gas
R = ideal gas constant
T = Absolute temperature of a gas
For initial and final states:

= 1.4