Nuclear Reactions and Radioactive Decay

The video covers the final chapter of physics for the MCAT, focusing on atomic and nuclear phenomena. It begins with the photoelectric effect, explaining how light of sufficient frequency can cause electron emission from metals. The video then discusses light absorption and emission, highlighting their importance in spectroscopy. It also covers nuclear binding energy and mass defect, explaining how mass is converted to energy in nuclear processes. Finally, the video explores nuclear reactions, including fusion and fission, and details various types of radioactive decay.

What is required for the photoelectric effect to occur?

• Light with a frequency that decreases over time

• Light with a frequency lower than the threshold frequency

• Light with a frequency equal to or higher than the threshold frequency

• Light with a wavelength longer than the threshold wavelength

Which constant is used to calculate the energy of a photon?

• Boltzmann's constant

• Newton's constant

• Avogadro's number

• Planck's constant

What happens when an electron absorbs a photon?

• It moves to a higher energy orbit

• It remains in the same orbit

• It moves to a lower energy orbit

• It emits another photon

In spectroscopy, what does the absorption of light by a molecule indicate?

• The molecule is moving to a higher energy state

• The molecule is changing its chemical structure

• The molecule is losing mass

• The molecule is emitting light

What is the mass defect in a nucleus?

• The difference between the mass of a nucleus and the sum of its protons and neutrons

• The mass of a nucleus after a nuclear reaction

• The mass of a nucleus before a nuclear reaction

• The mass of a nucleus compared to an electron

What type of nuclear reaction involves the splitting of a large nucleus?

• Fusion

• Fission

• Beta decay

• Alpha decay

Which type of decay involves the emission of a helium nucleus?

• Beta decay

• Gamma decay

• Electron capture

• Alpha decay

What is the half-life of a radioactive substance?

• The time it takes for the substance to completely decay

• The time it takes for half of the substance to decay

• The time it takes for the substance to double in mass

• The time it takes for the substance to emit all its energy

How does the rate of radioactive decay change as the number of nuclei decreases?

• The rate fluctuates randomly

• The rate decreases

• The rate remains constant

• The rate increases

If a sample starts with 200 grams and has a half-life of 3, how much remains after 3 half-lives?

• 200 grams

• 100 grams

• 25 grams

• 50 grams