Choose the correct option from the following options given below :

Solution

Physics sir · 3 steps

An orbiting electron accelerates, and an accelerating charge radiates, so Rutherford's atom must collapse.

1. Picture both models. In Thomson's model, electrons sit inside a uniform sphere of positive charge, like seeds in a watermelon. In Rutherford's model, all the positive charge and nearly all the mass sit in a tiny nucleus, and electrons revolve around it.

   Feature	Thomson's model	Rutherford's model
   Force on electron in ground state	Zero at its equilibrium position, so it is in stable equilibrium	Always a net force toward the nucleus, which supplies the centripetal force
   Mass distribution	Nearly continuous, spread over the whole atom	Highly non-uniform, packed into the nucleus
   Who carries most of the mass	The positive part	The positive part (the nucleus)
   Stable by classical physics?	Yes	No: the orbiting electron radiates energy and spirals into the nucleus

2. Why it collapses. An electron moving in a circle is always accelerating. Classical electromagnetism says an accelerating charge radiates energy. The electron keeps losing energy, its orbit keeps shrinking, and it falls into the nucleus in about 10⁻⁸ s.
3. So. Options (a) and (b) swap the two models, and (d) is wrong because the positive part holds most of the mass in both models. Only (c) is correct: a classical Rutherford atom is doomed to collapse.

The idea to keep. Circular motion means acceleration, and an accelerating charge radiates. That one fact is why classical physics cannot keep Rutherford's atom stable, and why Bohr had to add new rules.

Answer from the NTA final answer key. Solution by PrepWiser.