Vardaan Learning Institute - Science Mock Test 3

1. During anaerobic respiration in yeast, the products formed are:

(a) \(CO_2 + H_2O + Energy\)
(b) \(Lactic \ acid + Energy\)
(c) \(Ethanol + CO_2 + Energy\)
(d) \(Pyruvate + Energy\)

2. The gap between two neurons where the electrical signal is converted to a chemical signal is called:

(a) Dendrite
(b) Synapse
(c) Axon
(d) Cell body

3. Which of the following is an example of homologous organs?

(a) Wing of a bird and wing of a bat
(b) Wing of a bird and forelimb of a human
(c) Potato and sweet potato
(d) Wing of a butterfly and wing of a bat

4. The decomposers in an ecosystem:

(a) Convert inorganic material to simpler forms
(b) Convert organic material to inorganic forms
(c) Convert inorganic materials into organic compounds
(d) Do not break down organic compounds

5. Which of the following methods of contraception protects a person from acquiring sexually transmitted diseases (STDs)?

(a) Oral pills
(b) Copper-T
(c) Condom
(d) Surgery

6. Assertion (A): The energy flow in an ecosystem is unidirectional.
Reason (R): The energy captured by autotrophs does not revert back to the solar input.

(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

7. Assertion (A): Traits like tallness in pea plants are inherited independently.
Reason (R): Genes controlling different traits are located on different chromosomes or far apart on the same chromosome.

(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

8. State the function of the following plant hormones:
(a) Auxin
(b) Cytokinin (2 Marks)

9. What is the importance of DNA copying in reproduction? Why is variation beneficial to the species but not necessarily for the individual? (2 Marks)

10. Differentiate between aerobic and anaerobic respiration. Name one organism that uses the anaerobic mode. (2 Marks)

11. Describe the flow of blood in the human heart. Why is it called double circulation? (3 Marks)

12. How are fats digested in our bodies? Where does this process take place? Mention the role of bile salts. (3 Marks)

13. (a) Draw a neat diagram of the structure of a Neuron and label the parts: Dendrite, Cell Body, Axon.
(b) How does a nerve impulse travel across a synapse? (3 Marks)

14. Explain the process of formation of urine in the human kidney. (3 Marks)

15. Long Answer Question (5 Marks):
(a) Draw a longitudinal section of a flower and label: Anther, Stigma, Ovary, Style.
(b) What is pollination? How does it differ from fertilization?
(c) Explain the post-fertilization changes in a flower.

OR

(a) Name the main organs of the human male reproductive system.
(b) State the function of: (i) Testis, (ii) Vas deferens, (iii) Prostate gland.
(c) Why are testes located outside the abdominal cavity?

16. Case-based Question (4 Marks):
Mendel selected garden pea plants for his experiments. He selected tall plants (TT) and short plants (tt) and crossed them. He observed that all F1 progeny were tall. When he self-pollinated F1 plants, he obtained both tall and short plants in F2 generation.
(i) What is the phenotype ratio obtained in the F2 generation? (1 Mark)
(ii) What conclusion can be drawn from the F1 generation observation? (1 Mark)
(iii) (a) If 100 plants are produced in F2, how many are expected to be short? (2 Marks)
OR
(iii) (b) State Mendel's Law of Dominance derived from this experiment. (2 Marks)

17. Which of the following reactions involves the combination of two elements?

(a) \(CaO + CO_2 \rightarrow CaCO_3\)
(b) \(4Na + O_2 \rightarrow 2Na_2O\)
(c) \(SO_2 + \frac{1}{2}O_2 \rightarrow SO_3\)
(d) \(NH_3 + HCl \rightarrow NH_4Cl\)

18. A solution turns red litmus blue, its pH is likely to be:

(a) 1
(b) 4
(c) 5
(d) 10

19. Which of the following metals does not react with cold water but reacts with hot water?

(a) Sodium (Na)
(b) Potassium (K)
(c) Magnesium (Mg)
(d) Calcium (Ca)

20. The functional group present in Propanone is:

(a) Alcohol
(b) Aldehyde
(c) Ketone
(d) Carboxylic acid

21. Write the balanced chemical equation for the reaction of: (i) Iron with steam, (ii) Calcium with water. (2 Marks)

22. Why does distilled water not conduct electricity, whereas rain water does? Explain. (2 Marks)

23. What is the difference between Roasting and Calcination? Give one example of each. (2 Marks)

24. Assertion (A): Carbon forms covalent bonds with other atoms.
Reason (R): Carbon has 4 valence electrons and cannot gain or lose 4 electrons easily due to energy considerations.

(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

25. (a) Write the name and chemical formula of the main product formed when Ethanol is heated with alkaline \(KMnO_4\).
(b) Explain the cleansing action of soaps. Why are soaps not effective in hard water? (3 Marks)

26. (a) Identify the substance oxidised and reduced in the following reaction:
\(MnO_2 + 4HCl \rightarrow MnCl_2 + 2H_2O + Cl_2\)
(b) What is a redox reaction? Give another example. (3 Marks)

27. Case-based Question (4 Marks):
The pH of a solution is a measure of its acidity or alkalinity. Our stomach produces Hydrochloric acid which helps in digestion. During indigestion, the stomach produces too much acid causing pain. People use bases called antacids to neutralize the excess acid. Tooth decay starts when the pH of the mouth is lower than 5.5.
(i) Name a mild base often used as an antacid. (1 Mark)
(ii) Why does tooth decay start when pH is lower than 5.5? (1 Mark)
(iii) (a) Explain why bee-sting causes pain and irritation. What is the remedy? (2 Marks)
OR
(iii) (b) A farmer treats the soil of his field with quick lime (Calcium Oxide). What can you conclude about the nature of the soil? Explain. (2 Marks)

28. Long Answer Question (5 Marks):
(a) What are amphoteric oxides? Give two examples.
(b) Write balanced equations to show the reaction of Aluminium Oxide with (i) HCl, (ii) NaOH.
(c) Why is Sodium kept immersed in kerosene?

OR

(a) Draw the electron dot structure for (i) Ethanoic Acid, (ii) H2S.
(b) What is a homologous series? State two characteristics.
(c) Write the molecular formula of the second member of the homologous series of Alkenes.

29. Identify the compound X on the basis of the reactions given below. Also, write the name and chemical formulae of A, B and C.
(i) X + Zn → A + H₂
(ii) X + HCl → B + H₂O
(iii) X + CH₃COOH → C + H₂O (3 Marks)

30. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?

(a) Between the principal focus and the centre of curvature
(b) At the centre of curvature
(c) Beyond the centre of curvature
(d) Between the pole of the mirror and its principal focus

31. The human eye can focus on objects at different distances by adjusting the focal length of the eye lens. This is due to:

(a) Presbyopia
(b) Accommodation
(c) Near-sightedness
(d) Far-sightedness

32. Which of the following terms does not represent electrical power in a circuit?

(a) \(I^2R\)
(b) \(IR^2\)
(c) \(VI\)
(d) \(V^2/R\)

33. The magnetic field lines inside a long current carrying solenoid are:

(a) Curved
(b) Parallel straight lines
(c) Radial
(d) Concentric circles

34. A person needs a lens of power -5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre.
(a) Name the defects of vision the person is suffering from.
(b) Calculate the focal length of the lens required for correcting (i) distant vision, (ii) near vision. (3 Marks)

35. Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to the electric mains supply. What current is drawn from the line if the supply voltage is 220 V? (3 Marks)

36. (a) State the Right-Hand Thumb Rule.
(b) Draw the pattern of magnetic field lines produced around a current carrying straight conductor. Mark the direction of the current and the magnetic field. (3 Marks)

37. (a) Define the principal focus of a concave mirror.
(b) An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image. (3 Marks)

38. Long Answer Question (5 Marks):
(a) State Ohm's Law. Draw a circuit diagram to verify this law.
(b) Derive an expression for the equivalent resistance of three resistors R1, R2, and R3 connected in series.
(c) A wire of resistance 20 \(\Omega\) is bent to form a closed square. What is the resistance across a diagonal of the square?

OR

(a) What is meant by the heating effect of electric current? Derive the formula \(H = I^2Rt\).
(b) Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
(c) An electric iron consumes energy at a rate of 840 W when heating is at the maximum rate. The voltage is 220 V. Calculate the current and the resistance.

39. Case-based Question (4 Marks):
A student performs an experiment with a glass slab to trace the path of a ray of light. He observes that the emergent ray is parallel to the incident ray but is displaced sideways.
(i) Name the phenomenon observed when light passes from air to glass. (1 Mark)
(ii) State Snell's Law of refraction. (1 Mark)
(iii) (a) Draw a ray diagram showing the refraction through a rectangular glass slab. Label the angle of incidence and angle of emergence. (2 Marks)
OR
(iii) (b) If the refractive index of glass is 1.5, calculate the speed of light in glass. (Speed of light in vacuum = \(3 \times 10^8\) m/s). (2 Marks)