General Fundamental Scientific Principles 4 — Questions and Answers
Question 1: Which phase of matter has a definite volume but no definite shape?
- Solid
- Liquid (Correct answer)
- Gas
- Plasma
Correct answer: Liquid
Liquids have a fixed volume but take the shape of their container because their particles can flow past one another.
Question 2: What does a catalyst do in a chemical reaction?
- Increases the activation energy required
- Provides energy to start the reaction
- Lowers the activation energy without being consumed (Correct answer)
- Changes the products of the reaction
Correct answer: Lowers the activation energy without being consumed
A catalyst lowers the activation energy needed for a reaction to proceed and is not permanently consumed in the process.
Question 3: What is the principle behind a magnetic resonance imaging (MRI) scan?
- X-ray absorption by dense tissues
- Reflection of ultrasound waves
- Nuclear spin of hydrogen atoms in a magnetic field (Correct answer)
- Emission of gamma rays from radioactive tracers
Correct answer: Nuclear spin of hydrogen atoms in a magnetic field
MRI exploits the quantum spin of hydrogen nuclei, which align in magnetic fields and emit signals when disturbed by radio waves.
Question 4: Which law describes the relationship between the pressure and volume of a gas at constant temperature?
- Charles's Law
- Avogadro's Law
- Boyle's Law (Correct answer)
- Gay-Lussac's Law
Correct answer: Boyle's Law
Boyle's Law states that at constant temperature, the pressure of a gas is inversely proportional to its volume (P₁V₁ = P₂V₂).
Question 5: What is the name of the force that opposes the relative motion between two surfaces in contact?
- Gravity
- Tension
- Friction (Correct answer)
- Normal force
Correct answer: Friction
Friction is the resistive force that acts parallel to surfaces in contact and opposes their relative motion or tendency to move.
Question 6: In genetics, what term describes an allele that is only expressed when two copies are present?
- Dominant
- Co-dominant
- Recessive (Correct answer)
- Epistatic
Correct answer: Recessive
A recessive allele is only expressed in the phenotype when an organism carries two copies of it (homozygous recessive).
Question 7: Which electromagnetic waves have the shortest wavelength?
- Radio waves
- Visible light
- Ultraviolet rays
- Gamma rays (Correct answer)
Correct answer: Gamma rays
Gamma rays have the shortest wavelengths (below 10 picometers) and therefore the highest energy in the electromagnetic spectrum.
General Fundamental Scientific Principles 4
Which phase of matter has a definite volume but no definite shape?