An electron absorbs 5.0 × 10-19 J and moves from orbit P to orbit R. It then moves to orbit Q, emitting 2.0 × 10-19 J.
What happens when the electron returns from Q to P?
It emits 7.0×10−19 J7.0\times10^{-19}\ \mathrm{J}7.0×10−19 J.
It emits 3.0×10−19 J3.0\times10^{-19}\ \mathrm{J}3.0×10−19 J.
It absorbs 7.0×10−19 J7.0\times10^{-19}\ \mathrm{J}7.0×10−19 J.
It absorbs 3.0×10−19 J3.0\times10^{-19}\ \mathrm{J}3.0×10−19 J.
103 exam-style questions on Edexcel GCSE Physics 6.1 Atomic structure and isotopes, covering 6.1.1 Structure of the atom, 6.1.2 Isotopes: atomic and mass number, 6.1.3 Sub-atomic particles: masses and charges, and 6.1.4 Electron orbits and energy changes. Each one has a worked solution and a mark scheme showing where the marks go.