Prelims 2013 · archive
EasyThe known forces of nature can be divided into four classes, viz., gravity, electromagnetism, weak nuclear force and strong nuclear force. With reference to them, which one of the following statements is not correct?
Answer & explanation
Answer: (a) Gravity is the strongest of the four
Gravity is the weakest of the four fundamental forces, not the strongest; the strong nuclear force is the strongest. So statement (a) is the incorrect one.
- ✓ (a) This statement is wrong, so it is the answer. The strong force is the strongest of the four fundamental interactions. Gravity is the weakest, although its range is infinite.
- ✗ (b) This statement is true, so it is not the answer. Electromagnetism is the force that acts between electrically charged particles. It covers both electricity and magnetism.
- ✗ (c) This statement is true, so it is not the answer. The weak force can turn a down quark into an up quark, changing a neutron into a proton. This process occurs in radioactive decay, when atoms spontaneously shed energy and subatomic particles.
- ✗ (d) This statement is true, so it is not the answer. At the level of the atomic nucleus, the strong force holds protons and neutrons together.
Remember · Order of strength: strong > electromagnetic > weak > gravity. Gravity is the weakest but has infinite range. The weak force drives radioactive (beta) decay, and the strong force binds the nucleus.
Sources
- CERN – The Standard Model ↗ · reference work “The strong force, as the name suggests, is the strongest of all four fundamental interactions.”
- NASA Science – The Four Fundamental Forces ↗ “At the level of an atomic nucleus, the strong force holds together the protons and neutrons that form the essence of the elements. … This type of action also occurs in radioactive decay, which happens when atoms spontaneously shed energy and subatomic particles.”
Question: UPSC Civil Services (Preliminary) 2013, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·