In toasters, the force primarily used is the force of electricity. When you plug in a toaster and turn it on, it draws electrical energy from the power source. This energy is converted into heat through a heating element inside the toaster.
The heating element is usually made of nichrome wire, which has a high electrical resistance. When an electric current passes through the nichrome wire, it gets very hot, and this heat is what toasts the bread or other food items placed in the toaster.
Toasters also have a mechanism that allows you to lower and raise the bread slices. This mechanism typically involves a lever that you push down to lower the bread into the toaster slots. When the lever is released, springs inside the toaster push the toast back up.
While the force of electricity is the primary force used in toasters, the springs play a secondary role in the mechanical operation of the toaster, assisting in the lifting of the toast when it's done toasting.
In summary, electricity is the main force used for generating heat in toasters, while springs aid in the mechanical process of lowering and raising the bread.