IB Physics Flashcards

What does Einstein's equation E = mc² express?

Answer: Mass-energy equivalence

E = mc² expresses mass-energy equivalence, showing that mass can be converted to energy and vice versa, with c² as the conversion factor.

In nuclear physics, what is nuclear fission?

Answer: The splitting of a heavy nucleus into lighter nuclei

Nuclear fission is the process where a heavy nucleus (such as uranium-235) splits into two smaller nuclei, releasing a large amount of energy.

In the photoelectric effect, what happens when the intensity of light is increased without changing its frequency?

Answer: The number of emitted electrons increases

Increasing light intensity increases the number of photons hitting the surface, so more electrons are emitted, but their maximum kinetic energy stays the same.

What is absolute zero on the Kelvin temperature scale?

Answer: 0 K

Absolute zero is 0 K, the theoretical temperature at which particles have minimum thermal energy, equivalent to −273.15 °C.

Which gas law states that the pressure of an ideal gas is inversely proportional to its volume at constant temperature?

Answer: Boyle's Law

Boyle's Law states P ∝ 1/V at constant temperature, meaning doubling the volume of a gas halves its pressure.

In radioactive decay, what does 'half-life' mean?

Answer: The time for half the atoms in a sample to undergo radioactive decay

Half-life is the time required for exactly half the radioactive nuclei in a sample to decay, and it is constant for any given isotope.

Which subatomic particles are found in the nucleus of an atom?

Answer: Protons and neutrons

The nucleus contains protons (positively charged) and neutrons (no charge); electrons orbit the nucleus in shells outside it.