Achunk of coal has a substantial amount of chemical potential energy is released the chemical potential energy will cause the court atoms and molecules vibrate violently and this internal kinetic energy can be transferred to other nearby object which of these is the best way to transform this chemical potential energy into internal kinetic energy

like poles repel so keep pushing north to north and repels funny to see this

this would be about 43%

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.