Acertain 1.5-v battery (whose original mass is about 0.425 kg) has a capacity of 4.5 ah. about how much lighter is this battery when it is discharged than when it is full? it has the same number of electrons when discharged as it does when it is full.

i don't know that i agree with that but what's the question ?

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.