20 Flashcards
(21 cards)
What type of reaction is fire or combustion?
A chemical reaction between substances like carbon and oxygen.
Does fire use E = mc²?
No, fire is a chemical reaction and does not involve mass-energy conversion.
Why doesn’t mass change in a chemical reaction like combustion?
Because atoms are only rearranged, not created or destroyed.
What is the energy released when 0.50 kg of matter is converted to energy using E = mc²?
Enough to power 50 billion 10W light bulbs for a day.
How much more powerful is nuclear burning compared to chemical burning of hydrogen?
About 630 million times more powerful.
What is the key equation relating mass and energy?
E = mc²
What process in stars turns hydrogen into helium and releases energy?
Nuclear fusion.
What is the ‘missing mass’ in nuclear fusion reactions?
About 0.7% of mass is converted into energy.
What two particles are created alongside helium in hydrogen fusion?
Neutrino and positron.
What is a neutrino?
A nearly massless, neutral particle that travels from the Sun’s core to Earth.
How fast do neutrinos reach the Sun’s surface compared to photons?
Neutrinos take 2 seconds, photons take 200,000 years.
Why is nuclear fusion hard to achieve on Earth?
It requires temperatures over 10 million K to overcome proton repulsion.
What happens when matter and anti-matter meet?
They annihilate into pure energy, typically gamma photons.
What is the formula for energy released during pair annihilation?
E = 2mc²
What is pair production?
A gamma photon converts into an electron and a positron.
What must be conserved during pair production?
Electric charge and energy must be conserved.
Why is anti-matter difficult to store?
It annihilates instantly when it contacts regular matter.
What is the energy equivalent of a small H-bomb (4.18×10^16 J) in grams of antimatter?
230 grams of antimatter would produce this much energy.
What is a practical medical use of antimatter?
PET (Positron Emission Tomography) scans.
What does the Large Hadron Collider do?
It accelerates particles to near-light speed and smashes them to study fundamental physics.
Why is it impossible to store antimatter in a container?
Because antimatter annihilates instantly upon contact with normal matter, and no known container made of matter can prevent that. You’d need magnetic or vacuum containment (like in sci-fi or particle physics labs).
