A sample of 2.50 kg of water is held at a temperature of 100°C. How much energy must be added to completely turn the liquid water to water vapor?
(The latent heat of vaporization for water is 2260 kJ/kg; the latent heat of
fusion for water is 333 kJ/kg.)
A. 833 kJ
B. 5650 kJ
C. 133 kJ
D. 904 kJ

conservation of mass

mass before something happens = mass afterwards

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.