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General Knowledge · Class 12 · Science and space

Big ideas: relativity, quantum and AI

The map on your phone would drift off by kilometres every day if engineers ignored an idea Albert Einstein published in 1905. Which idea?

Small test at the end: scroll down to the end of this page for five short questions that check what you have learnt. Tap an answer, then press Check answer. Go to the questions ↓

Jump to: Read first · Try it away from the screen · Check it yourself · Check yourself · For teachers

Read first

5 facts. The questions below make you use them, not just remember them.

  1. Einstein's relativity says the speed of light, about 300,000 km a second, is the same for everyone, and that time runs at different rates depending on speed and gravity.
  2. GPS satellites carry precise clocks. Because of relativity, those clocks gain about 38 millionths of a second a day compared with clocks on the ground. Without correction, positions would drift by kilometres each day.
  3. Quantum physics describes the very small: energy comes in tiny packets, and light behaves both as a wave and as a stream of particles. Satyendra Nath Bose of Kolkata did key work in 1924, and particles called bosons are named after him.
  4. C. V. Raman discovered in 1928 that light scattered by molecules changes slightly in colour. This Raman effect won him the Nobel Prize in 1930. India celebrates National Science Day on 28 February, the day of his discovery.
  5. Today's AI systems learn patterns from huge amounts of data. Chatbots predict likely words, so they can sound sure and still be wrong. Always check important facts from an AI with a reliable source.

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Try it away from the screen

Ask an AI chatbot, or an older person, three questions whose answers you can check in your textbook. Score how many answers were fully right. What does that tell you about trusting a confident answer?

Make it on paper. Keep it with you. Nothing to upload.

Check it yourself

Science news often uses words like "breakthrough" or "proves Einstein wrong". Look for the original research paper or a university press release, and check whether other scientists agree.

Check yourself

Five questions about what this page teaches. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.

  1. Question 1 of 5Which particles are named after Satyendra Nath Bose?

    See the answer and why
    • A. Ramans Not this one. There are no particles called ramans. Raman discovered an effect of light.
    • B. Bosons Correct. Yes. The Higgs boson is one famous example.
    • C. Protons Not this one. Protons were named by Ernest Rutherford.
    • D. Electrons, which move around the nucleus of every atom Not this one. Electrons were named in the 1890s, long before Bose's work.
  2. Question 2 of 5Why must GPS engineers correct the satellites' clocks for relativity?

    See the answer and why
    • A. Time runs at a slightly different rate up there, and errors add up Correct. Yes. Tiny daily differences would grow into kilometres of error.
    • B. The satellites are in a different time zone Not this one. Time zones are human labels. The difference is physical.
    • C. The clocks are cheap and break Not this one. They are very precise atomic clocks.
    • D. Light does not travel in space at all, so signals must be re-sent many times Not this one. Light travels very well through space.
  3. Question 3 of 5Light travels about 300,000 km a second. The Moon is about 384,000 km away. About how many seconds does moonlight take to reach us?

    See the answer and why
    • A. 12.8 Not this one. Check: 12.8 × 300,000 is 3,840,000 km, ten times too far.
    • B. 1.28 Correct. Yes. 384,000 ÷ 300,000 = 1.28 seconds.
    • C. 128 Not this one. Check the zeros: 384,000 ÷ 300,000 is a little more than 1.
    • D. 0.78 Not this one. That divides the other way round: 300,000 ÷ 384,000.
  4. Question 4 of 5An AI chatbot gives you a confident answer for a school project. What should you do?

    See the answer and why
    • A. Use it, because computers do not make mistakes Not this one. AI systems do make mistakes, sometimes convincing ones.
    • B. Check it in a reliable source before you use it Correct. Yes. Chatbots can be confidently wrong.
    • C. Use it if it sounds professional and has long words Not this one. Sounding professional is not the same as being right.
    • D. Ask the same chatbot again and use the second answer Not this one. Asking the same tool again does not check it.
  5. Question 5 of 5What did C. V. Raman discover?

    See the answer and why
    • A. Light scattered by molecules changes slightly in colour Correct. Yes. The Raman effect is used today to identify substances.
    • B. Radio waves Not this one. Radio waves were shown by Hertz and J. C. Bose in the 1880s and 1890s.
    • C. The speed of light Not this one. The speed of light was measured long before Raman.
    • D. That the sky is blue because it reflects the colour of the sea Not this one. The sky is blue because air scatters blue light more. It is not a reflection of the sea.

For teachers and grown-upsWhere the facts come from, and how to use this round.

Sources and notes
  • GPS relativity: satellite clocks run fast by about 38 microseconds a day (45 from weaker gravity, minus 7 from speed).
  • Bose's 1924 paper was sent to Einstein, who translated it; Bose-Einstein statistics. Raman effect: 28 February 1928.
  • The AI task: do not share personal details with any chatbot.
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