Which of the following statements about sanitary landfills is correct? Landfills are lined with impermeable materials to prevent leakage into the groundwater
Capped landfills may become golf cources or parks?
All of these choices are correct
Landfills are capped when they become full to prevent contamination?

0.19 m/s and 0.45 m/s

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.