Natural Sciences Admissions Assessment (NSAA) — Questions and Answers

Question 1: A light ray passes from air into glass and bends toward the normal. This is because in glass the light:

Has longer wavelength
Has higher frequency
Travels faster
Travels slower (Correct answer)

Correct answer: Travels slower

Light slows down when entering a denser medium, causing refraction toward the normal.

Question 2: What happens to the resistance of a metallic conductor as its temperature increases?

Drops to zero
Increases (Correct answer)
Remains constant
Decreases

Correct answer: Increases

In metallic conductors, higher temperature increases lattice vibrations, increasing resistance.

Question 3: Which of the following processes results in the formation of gametes?

Meiosis (Correct answer)
Budding
Mitosis
Binary fission

Correct answer: Meiosis

Meiosis is the process that results in the formation of gametes (sperm and eggs), reducing the chromosome number by half.

Question 4: Which of the following is a factor of x² - 5x + 6?

(x + 3)
(x + 6)
(x - 2) (Correct answer)
(x - 1)

Correct answer: (x - 2)

x² - 5x + 6 = (x-2)(x-3), so (x-2) is a factor.

Question 5: What is the intensity relationship between two points at distances r₁ and r₂ from a point source?

I₁/I₂ = r₂/r₁
I₁/I₂ = r₁/r₂
I₁/I₂ = (r₁/r₂)²
I₁/I₂ = (r₂/r₁)² (Correct answer)

Correct answer: I₁/I₂ = (r₂/r₁)²

Intensity from a point source follows the inverse square law: I ∝ 1/r², so I₁/I₂ = (r₂/r₁)².

Question 6: A box has 3 defective and 7 non-defective items. Two items are drawn without replacement. What is the probability both are defective?

9/100
3/10
6/90
1/15 (Correct answer)

Correct answer: 1/15

P(both defective) = (3/10) × (2/9) = 6/90 = 1/15.

Question 7: Which of the following statements about enzymes is true?

Enzymes work equally well at all pH levels
Enzymes decrease the activation energy of a reaction (Correct answer)
Enzymes are specific to a single type of reaction
Enzymes are consumed during the reaction they catalyze

Correct answer: Enzymes decrease the activation energy of a reaction

Enzymes function by lowering the activation energy required for a reaction to occur, thereby speeding up the reaction.

Question 8: Find the area under y = x² between x = 0 and x = 3.

3
9 (Correct answer)
27
6

Correct answer: 9

∫₀³ x² dx = [x³/3]₀³ = 27/3 - 0 = 9.

Question 9: Which organelle is responsible for producing ATP through oxidative phosphorylation?

Lysosome
Mitochondrion (Correct answer)
Nucleus
Ribosome

Correct answer: Mitochondrion

The mitochondrion is responsible for producing ATP through oxidative phosphorylation in the process of cellular respiration.

Question 10: A bag contains 4 red, 3 blue, and 5 green balls. What is the probability of drawing a blue ball?

1/4 (Correct answer)
1/3
1/5
1/6

Correct answer: 1/4

P(blue) = 3/(4+3+5) = 3/12 = 1/4.

Question 11: What is the derivative of f(x) = 5x³ - 2x + 7?

5x² - 2
15x² - 2 (Correct answer)
15x² + 2
15x³ - 2

Correct answer: 15x² - 2

Using power rule: d/dx(5x³) = 15x², d/dx(-2x) = -2, d/dx(7) = 0; so f'(x) = 15x² - 2.

Question 12: Which of the following compounds is ionic?

H₂O
CO₂
NaCl (Correct answer)
CH₄

Correct answer: NaCl

Sodium chloride (NaCl) is an ionic compound, consisting of positively charged sodium ions and negatively charged chloride ions.

Question 13: If 5^x = 125, what is x?

4
25
2
3 (Correct answer)

Correct answer: 3

125 = 5³, so 5^x = 5³ → x = 3.

Question 14: What is the expected value of a fair six-sided die roll?

3
6
4
3.5 (Correct answer)

Correct answer: 3.5

E(X) = (1+2+3+4+5+6)/6 = 21/6 = 3.5.

Question 15: Which statement correctly expresses the second law of thermodynamics?

The entropy of a perfect crystal at absolute zero is zero
Systems in equilibrium have the same pressure
The entropy of an isolated system tends to increase in irreversible processes (Correct answer)
The total energy of an isolated system is constant

Correct answer: The entropy of an isolated system tends to increase in irreversible processes

The second law states that natural processes in isolated systems proceed in the direction of increasing entropy.

Question 16: Which of the following is the correct electron configuration for a neutral atom of sulfur (atomic number 16)?

1s² 2s² 2p⁶ 3s² 3p³
1s² 2s² 2p⁶ 3s² 3p⁶
1s² 2s² 2p⁶ 3s² 3p⁴ (Correct answer)
1s² 2s² 2p⁶ 3s¹ 3p⁵

Correct answer: 1s² 2s² 2p⁶ 3s² 3p⁴

The electron configuration for sulfur, which has 16 electrons, is 1s² 2s² 2p⁶ 3s² 3p⁴.

Question 17: What is the SI unit of temperature used in thermodynamic equations?

Celsius (°C)
Fahrenheit (°F)
Rankine (°R)
Kelvin (K) (Correct answer)

Correct answer: Kelvin (K)

The Kelvin is the SI unit of thermodynamic temperature, defined so that absolute zero is 0 K.

Question 18: A capacitor stores 0.01 C of charge at a potential difference of 5 V. What is its capacitance?

0.05 F
0.005 F
0.002 F (Correct answer)
0.02 F

Correct answer: 0.002 F

Capacitance C = Q/V = 0.01/5 = 0.002 F.

Question 19: The median of the data set {3, 7, 9, 2, 5} is:

9
7
5 (Correct answer)
3

Correct answer: 5

Sorted: {2, 3, 5, 7, 9}; middle value = 5.

Question 20: The integral ∫ 1/x dx equals:

x + C
ln|x| + C (Correct answer)
e^x + C
-1/x² + C

Correct answer: ln|x| + C

∫ 1/x dx = ln|x| + C.

Question 21: What is the molecular geometry of methane (CH₄)?

Trigonal planar
Linear
Tetrahedral (Correct answer)
Bent

Correct answer: Tetrahedral

Methane (CH₄) has a tetrahedral molecular geometry, with four hydrogen atoms symmetrically distributed around the central carbon atom.

Question 22: In which phase of the cell cycle does DNA replication occur?

G1 phase
M phase
G2 phase
S phase (Correct answer)

Correct answer: S phase

DNA replication occurs during the S phase (synthesis phase) of the cell cycle.

Question 23: What type of reaction is represented by the following equation: 2H₂ + O₂ → 2H₂O?

Synthesis (Correct answer)
Single displacement
Decomposition
Double displacement

Correct answer: Synthesis

The given equation represents a synthesis reaction, where two or more reactants combine to form a single product.

Question 24: In the periodic table, which trend is observed as you move from left to right across a period?

Electronegativity decreases
Metallic character decreases (Correct answer)
Ionization energy decreases
Atomic radius increases

Correct answer: Metallic character decreases

As you move from left to right across a period, elements become less metallic and more non-metallic in character.

Question 25: Which type of intermolecular force is the strongest?

Van der Waals forces
London dispersion forces
Dipole-dipole interactions
Hydrogen bonds (Correct answer)

Correct answer: Hydrogen bonds

Hydrogen bonds are the strongest type of intermolecular force compared to London dispersion forces and dipole-dipole interactions.

Question 26: Which of the following compounds will exhibit hydrogen bonding?

H₂S
NH₃ (Correct answer)
CH₄
CO₂

Correct answer: NH₃

Ammonia (NH₃) exhibits hydrogen bonding due to the presence of a highly electronegative nitrogen atom bonded to hydrogen atoms.

Question 27: What is the primary role of chlorophyll in photosynthesis?

Releasing oxygen
Absorbing light energy (Correct answer)
Synthesizing glucose
Absorbing water

Correct answer: Absorbing light energy

Chlorophyll is the pigment in plants that absorbs light energy, which is then used to convert carbon dioxide and water into glucose during photosynthesis.

Question 28: The product rule for differentiation states: d/dx[f(x)g(x)] =

f'(x)g(x) + f(x)g'(x) (Correct answer)
f'(x)g'(x)
f(x)/g'(x)
f'(x)g(x) - f(x)g'(x)

Correct answer: f'(x)g(x) + f(x)g'(x)

The product rule: d/dx[f(x)g(x)] = f'(x)g(x) + f(x)g'(x).

Question 29: What is the momentum of a 0.5 kg ball moving at 12 m/s?

12 kg·m/s
24 kg·m/s
3 kg·m/s
6 kg·m/s (Correct answer)

Correct answer: 6 kg·m/s

Momentum p = mv = 0.5 × 12 = 6 kg·m/s.

Question 30: Which of the following is the primary structure of a protein?

The sequence of amino acids (Correct answer)
The shape formed by disulfide bridges and ionic bonds
The three-dimensional shape formed by hydrogen bonding
The overall shape formed by interactions between multiple polypeptide chains

Correct answer: The sequence of amino acids

The primary structure of a protein is the linear sequence of amino acids in its polypeptide chain.

Natural Sciences Admissions Assessment (NSAA)

The NSAA is a Cambridge University admissions test for Natural Sciences applicants, assessing scientific reasoning and mathematical ability across Mathematics, Physics, Chemistry, and Biology through two timed sections of multiple-choice questions.

Questions

60 min

Time Limit

70%

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