GCSE GCSE Combined Science 1 — Questions and Answers
Question 1: What is the equation for photosynthesis?
- Glucose + Oxygen → Carbon dioxide + Water
- 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (Correct answer)
- CO₂ + H₂O → CH₂O + O
- C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
Correct answer: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
The balanced equation for photosynthesis is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (using light energy). Plants use carbon dioxide and water to produce glucose and oxygen.
Question 2: What is the difference between mitosis and meiosis?
- Mitosis produces 4 genetically unique cells; meiosis produces 2 identical cells
- Mitosis produces 2 identical daughter cells (for growth/repair); meiosis produces 4 genetically unique gametes (for reproduction) (Correct answer)
- Both are the same process
- Meiosis occurs only in plants
Correct answer: Mitosis produces 2 identical daughter cells (for growth/repair); meiosis produces 4 genetically unique gametes (for reproduction)
Mitosis produces 2 genetically identical diploid cells (same number of chromosomes as parent) for growth, repair, and asexual reproduction. Meiosis produces 4 genetically unique haploid cells (gametes) for sexual reproduction.
Question 3: What is Newton's Second Law of Motion?
- Every action has an equal and opposite reaction
- Force = mass × acceleration (F = ma) (Correct answer)
- An object stays at rest unless acted on by a force
- Momentum = mass × velocity
Correct answer: Force = mass × acceleration (F = ma)
Newton's Second Law states that the resultant force acting on an object equals its mass multiplied by its acceleration: F = ma. The greater the force or the smaller the mass, the greater the acceleration.
Question 4: What is an ionic bond?
- A bond formed by sharing electrons
- A bond formed by transferring electrons from a metal to a non-metal, creating oppositely charged ions (Correct answer)
- A bond between two non-metals
- A weak bond between molecules
Correct answer: A bond formed by transferring electrons from a metal to a non-metal, creating oppositely charged ions
An ionic bond forms when a metal atom transfers electrons to a non-metal atom. This creates positive metal ions and negative non-metal ions, which are held together by electrostatic attraction.
Question 5: What is the relationship between frequency, wavelength, and wave speed?
- Speed = frequency ÷ wavelength
- Speed = frequency + wavelength
- Speed = frequency × wavelength (Correct answer)
- Frequency = speed × wavelength
Correct answer: Speed = frequency × wavelength
Wave speed = frequency × wavelength (v = fλ). This applies to all waves — light, sound, and water waves. Rearranged: f = v/λ or λ = v/f.
Question 6: What is the half-life of a radioactive substance?
- The time for all of the substance to decay
- The time for half of the radioactive nuclei in a sample to decay (Correct answer)
- The total amount of radiation emitted
- The energy released per decay
Correct answer: The time for half of the radioactive nuclei in a sample to decay
Half-life is the time taken for half the radioactive atoms in a sample to decay. After one half-life, half remain; after two, a quarter remain; after three, an eighth, and so on.
GCSE GCSE Combined Science 1
What is the equation for photosynthesis?