In ancient times there was one great kingdom on whose throne was a just but cruel king named Physicus. King Physicus had his subjects. There were a total of ten subjects. At the end of each year, each of them brought the king ten bars of gold. Each gold bar weighed one kilogram. So, each subject had to hand over ten kilograms of gold to the king. The king's spy informed King Physicus that one subject was making a hundred grams lighter bar, but that they looked the same in size, the only difference was in the density of the gold. King Physicus was a wise man and with one measurement on the scales he found out which subject was stealing from him. The question is: how did King Physicus find out who the thief was with just one measurement?

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force