NDA Physics · Modern Physics
Scientists and Discoveries: Match the Pair
A pure-recall table of who discovered or explained what in modern physics — Chadwick (neutron), Einstein (photoelectric effect, relativity), Marie Curie (radium), and the LIGO confirmation of gravitational waves.
Why this matters
Three PYQs, all match-the-pair recall. The NDA presents a list of scientist-discovery pairs and asks which are correctly matched, so the only preparation is memorising the table cold. Get the famous swaps right (Chadwick = neutron, not photoelectric effect) and these are free marks.
Concept 1 of 2: Key modern-physics discoveries and their scientists
Definition
Landmark discoveries and their scientists:
- James Chadwick — discovered the neutron.
- Albert Einstein — explained the photoelectric effect; gave relativity and .
- Marie Curie — discovered radium (and polonium); pioneered radioactivity research.
- Rutherford — discovered the nucleus (alpha scattering).
- J. J. Thomson — discovered the electron.
- Niels Bohr — model of stable electron orbits.
| Scientist | Discovery / contribution |
|---|---|
| James Chadwick | Neutron |
| Albert Einstein | Photoelectric effect explanation; relativity (E = mc²) |
| Marie Curie | Radium (and polonium); radioactivity NDA 2021 — in the match list, only "Marie Curie : Radium" was correctly matched (Chadwick was wrongly paired with photoelectric effect, Einstein with neutron). |
| Ernest Rutherford | Atomic nucleus (alpha scattering) |
| J. J. Thomson | Electron (cathode rays) |
| Niels Bohr | Stable electron orbits (Bohr model) |
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
Example 1 · Modern Physics · Scientists and Discoveries
Chadwick = neutron, Einstein = photoelectric effect
Concept 2 of 2: LIGO — confirming gravitational waves and general relativity
Definition
LIGO = Laser Interferometer Gravitational-wave Observatory.
- LIGO made the first direct detection of gravitational waves (2015).
- This confirmed a key prediction of Einstein's General Theory of Relativity.
- A separate but related recall fact: LED = Light Emitting Diode (a semiconductor device that emits light when current flows).
| Item | Fact |
|---|---|
| LIGO full form | Laser Interferometer Gravitational-wave Observatory |
| LIGO confirmed | Gravitational waves predicted by Einstein's General Theory of Relativity NDA 2024 — the LIGO experiment confirmed a prediction of the General Theory of Relativity. |
| LED full form | Light Emitting Diode (a semiconductor device)Q |
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
Example 2 · Modern Physics · Scientists and Discoveries
LIGO confirmed GENERAL relativity (via gravitational waves)
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Reference tables (2)
Key modern-physics discoveries and their scientists6 rows
| Scientist | Discovery / contribution |
|---|---|
| James Chadwick | Neutron |
| Albert Einstein | Photoelectric effect explanation; relativity (E = mc²) |
| Marie Curie | Radium (and polonium); radioactivity NDA 2021 — in the match list, only "Marie Curie : Radium" was correctly matched (Chadwick was wrongly paired with photoelectric effect, Einstein with neutron). |
| Ernest Rutherford | Atomic nucleus (alpha scattering) |
| J. J. Thomson | Electron (cathode rays) |
| Niels Bohr | Stable electron orbits (Bohr model) |
LIGO — confirming gravitational waves and general relativity3 rows
| Item | Fact |
|---|---|
| LIGO full form | Laser Interferometer Gravitational-wave Observatory |
| LIGO confirmed | Gravitational waves predicted by Einstein's General Theory of Relativity NDA 2024 — the LIGO experiment confirmed a prediction of the General Theory of Relativity. |
| LED full form | Light Emitting Diode (a semiconductor device)Q |
Watch out for (2)
- Chadwick = neutron, Einstein = photoelectric effect→ Key modern-physics discoveries and their scientists
- LIGO confirmed GENERAL relativity (via gravitational waves)→ LIGO — confirming gravitational waves and general relativity
Test yourself on Modern Physics
10 past NDA questions from this chapter, timed at 10 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.