10 Class Science Pre Board Exam 2023-24: N. K. Bagrodia

10 Class Science Pre Board : Pre Board Exam 2023-24: N.K. Bagrodia Public School, Rohini

School Name:	N. K. Bagrodia Public School, Sector 9, Rohini, New Delhi 110085 India
Class:	10th Standard (CBSE)
Subject:	Science
Time Duration:	03 Hours
Maximum Marks:	80
Date:	~ January 2024

General Instructions:

1. This question paper of 39 questions in 5 sections.
2. All questions are compulsory. However, internal choices have been provided in some questions. A student is expected to attempt only one of these.
3. Section A consists of 20 objective type questions carrying 1 mark each.
4. Section B consists of 6 Very Short Answer type questions carrying 02 marks each. Answer to these questions should be in range of 30 to 50 words.
5. Section C consists of 7 Short Answer type questions carrying 03 marks each. Answer to these questions should be in range of 50 to 80 words.
6. Section D consists of 3 Long Answer type questions carrying 05 marks each. Answer to these questions should be in range of 80 to 120 words.
7. Section E consists of 3 source-based / case-based units of assessment of 04 marks each with sub-parts ‘a’, ‘b’ and ‘c’. Part ‘a’ and ‘b’ are compulsory. However internal choice is provided in part ‘c’.

Section-A

Question: 01. The following reaction is used for the preparation of oxygen gas in the laboratory.

Which of the following statement(s) is (are) correct about the reaction?

1. It is a decomposition reaction and endothermic in nature.
2. It is a combination reaction.
3. It is a decomposition reaction and accompanied by release of heat.
4. It is a photochemical decomposition reaction and exothermic in nature.

Question: 02. Few drops of aqueous solution of ammonium chloride are put on a universal indicator paper. The paper turns pink.

Study the following table and chose the correct option:

Question: 03. Select the appropriate state symbols of the product given as ‘X’ and ‘Y’ in the following chemical’ equation by choosing the correct option from the table given below:

Question: 04. Consider the following chemical equations I and II:

The correct statement about these equations is:

1. ‘I’ is a displacement reaction and ‘II’ is a decomposition reaction.
2. ‘I’ is a displacement reaction and ‘II’ is a double displacement reaction.
3. Both ‘I’ and ‘II’ are displacement reactions.
4. Both ‘I’ and are double displacement reactions.

Question: 05. Payal has to arrange the following in decreasing order of hydroxide ion concentration:

10 Class General Science Pre Board Exam – Question: 06. Ethane with the molecular formula C₂H₆ has:

1. 6 Covalent Bond
2. 7 Covalent Bond
3. 8 Covalent Bond
4. 9 Covalent Bond

Question: 07. In which of the following setups would the bulb glow.

1. (i) and (ii)
2. (i) and (iv)
3. (ii), (iii) and (iv)
4. (i), (ii) and (iv)

Question: 08. Given below is a diagram of nephron.

Which row of the following table correctly shows where filtration and selective reabsorption occur?

Question: 09.

• Name one excretory product other than oxygen and carbon dioxide in plants.
• Name any one substance other than water, that is reabsorbed during urine formation.

Question: 10. Classify the following movements as tropic or nastic:

• Opening of flower
• Twirling of tendrils

Question: 11.

‘Plant growth regulators do not always promote growth.’ Cite one example in support of the given statement and mention the action of the same.

Question: 12. Sex determination is regulated by environmental factors in

1. Humans
2. Lizards
3. Snail
4. Both (b) and (c)

Question: 13.

Rays of sun converge at a point 15 cm in front of a Concave Mirror. Where should an object be placed so that size of its image is equal to the size of the object?

1. 15 cm in front of the mirror
2. 30 cm in front of the mirror
3. between 15 and 30 cm in front of the mirror
4. more than 30 cm in front of the mirror.

Question: 14. Focal length of the eyes lens increases when eye muscles

1. are relaxed and lens becomes thinner
2. contract and lens becomes thicker
3. are relaxed and lens becomes thicker
4. contract and lens becomes thinner

Question: 15. Why are acquired traits generally not inherited over generations?

Question: 16. The separation of the right side and the left side of human heart is useful to:

1. keep oxygenated blood from mixing with deoxygenated blood
2. allow a slow supply of oxygen in the body
3. supply energy to animals with low energy needs
4. often change their body temperature

Question 17 to 20 are Assertion Reasoning based questions.

These consists of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:

• Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of (A)
• Both (A) and (R) are true, but (R) is not the correct explanation of (A)
• (A) is true, but (R) is false
• (A) is false, but (R) is true

Question: 17.

Assertion (A): in the following reaction

ZnO + C → Zn + CO
ZnO undergoes reduction

Reason (R): Carbon is a reducing agent that reduces ZnO to Zn.

Question: 18.

Assertion: On a cloudy day, the rate of photosynthesis will decrease.
Reason : The stomata close, leading to reduced transpiration.

Question: 19.

Assertion: Electric appliances with metallic body have three pin connections, whereas an electric bulb has two pin connections
Reason: Three pin connections reduce heating of connecting wires.

Question: 20.

Assertion: In male reproductive system, transport of sperm takes place in a fluid which also provide nutrition. Reason: Prostrate gland and seminal vesicles secrete in the vas deferens.

Section-B

Question: 21. With reference to the electro refining of impure copper, answer the following:

• What is the electrolyte used?
• Name the Cathode and Anode used?

Question: 22. State two reasons why absorption of digested food occurs mainly in the small intestine

10 Class Science Pre Board – Question: 23.

1. Name two structures involved in exchange of gases in plants.
2. State the significance of residual volume of air in lungs.

OR

How are lungs designed in human beings to maximize the area for exchange of gases?

Question: 24.

A ray of light, enters from glass to air and undergoes bending as shown in the figure. Find the refractive index of glass.

Question: 25.

An overhead wire carries a current in the East to West direction as shown in the figure. What will be the direction of magnetic field below the wire? Which rule is used to find this direction of magnetic field?

OR

What is the difference between a direct current and alternating current? How many times does AC, useaS in India, change direction in one second?

Question: 26. State two structural differences between arteries and veins.

Section-C

Question: 27. 

A metal ‘M’ on reacting with dilute acid liberates as gas ‘G’. The same metal also liberates gas ‘G’ when reacts with base.

1. Write the name of gas ‘G’.
2. How will you test the presence of this gas?
3. Write chemical equations for the reactions of the metal with (i) an acid and (ii) a base.

Question: 28.

1. Sometimes the pH of our mouth gets lower than 5.5, why?
2. A basic salt ‘X’ is obtained by heating baking soda followed by crystallisation. Identify ‘X’ and write reaction. State its two industrial uses.
3. Why do copper sulphate crystals turns white on heating.

OR

1. Explain the formation of CaCl₂ by the transfer of electrons.
2. Name the ions present in the compound.
3. Write about the solubility of these compounds.

Question: 29.

Two pea plants – one with round yellow seeds (RRYY) and another with wrinkled green (rryy) seeds produced F1 progeny that have round yellow seeds.

When F1 plants are self pollinated, which new combination of characters is expected in F2 progeny? How many seeds with these new combinations of characters will be produced when a total 160 seeds are produced in F2 generation? Explain with reason.

OR

1. Name the two types of gametes produced by men.
2. Does a male child inherit X-chromosome from his father? Justify.
3. How many types of gametes are produced by a human female?

Question: 30.

1. What will be the amount of energy available to the organism of the 2^nd trophic level of food chain, if theilikd available at the first trophic level is 10,000 joules?
2. We do clean natural ponds or lakes but an aquarium needs to be cleaned regularly. Why it is so?
3. List one harmful impact each of biodegradable and non-biodegradable waste.

Question: 31. Draw a ray diagram to show the refraction of light through a prism. Mark (1) angle of incidence, (2) Angle of emergence (3) Angle of deviation in the diagram.

Question: 32. What is meant by electrical resistivity of a material? Obtain its S.I. unit. What are the factors on which resistance of a wire depends?

Question: 33.

1. An electrical fuse is rated at 2A, what does this mean?
2. An electric iron of 1KW is operated at 220V. Which of the following fuses that are respectively rated at 1A, 3A and 5A can be used in it? (1+2)

Section-D

Question: 34.

1. Two compounds have same molecular formula C3H60. Write the structural formula of these compounds.
2. Draw all possible isomers of butane?
3. Identify the functional group present in the following compound.
   
4. A compound ‘X’ on &imbligron gives -a yellow flame with lots of smoke. What inference would you draw from this statement.
5. Name two oxidising agents that are used for the conversion of alcohol to acids.

OR

1. Write the structural formula of Benzene C₆H₄
2. Draw the electron dot structure of the gas molecule which is liberated when Zn metal is treated with aqueous NaOH solution.
3. Generate a homologous series containing the functional group ‘-COOH’ upto four carbons.
4. Name the functional group present in Propanone.
5. A gas is evolved when ethanol reacts with sodium. Write the balanced chemical equation of the reaction involved.

10 Class Science Pre Board – Question: 35.

1. Draw a well labelled diagram of human female reproductive system.
2. Describe the structure and function of placenta.
3. State in brief two advantages of adopting contraceptive methods.

OR

1. List two advantages of growing grapes or banana plants through vegetative propagation.
2. Diagrammatically explain the process of budding in Hydra.
3. Name the following:
   (i) Thread like non reproductive structures present in Rhizopus.
   (ii) ‘Blobs’ that develop at the tips of the non – reproductive threads in Rhizopus.

Question: 36. A student focussed the image of a candle flame on a white screen using a convex lens. He notes the position of the candle, screen and the lens as under:

Position of candle = 12.0 cm
Position of convex lens = 50.0 cm
Position of screen = 88.0 cm

1. What is the focal length of the Convex lens?
2. Where will the image be formed if he shifts the candle towards the lens at a position of 31.0 cm.
3. What will be the nature of the image formed if he further shifts the candle towards the lens?
4. Draw a ray diagram to show the formation of the image in case (iii) as stated above.

OR

A student is unable to see clearly the words on the blackboard from a distance of 4m, but can see clearly from a distance less than 4m. Name the defect of the vision the boy is suffering from. What is the nature and focal length of the lens, required to correct this defect. Draw ray diagram for:
(a) Defect of vision
(b) for its correction

Section-E

Q.37 to Q39 are case based / data based questions with 3 sub parts. Internal choice is provided in one,of these sub parts.

Question: 37.

Metals are required for a variety of purposes. For this we need their extraction from their ores. Ores are mined from the earth are normally contaminated with many impurities which must be removed prior to the extraction of metals. The extraction of pure metal involves the following steps:

1. Concentration of ores.
2. Extraction of metal from the concentrated ore.
3. Refining of the metals.
   (a) Name an ore of Mercury and State its formula.
   (b) What happens to Zinc Carbonate when it is heated strongly in limited supply of ore.
   (c) The reaction of metal A with Fe2O3 is highly exothermic and is used to join railway tracks.
   (i) Identify the metal A and name the reaction taking place.
   (ii) Write the chemical equation for the reaction of metal A with Fe2O3.

OR

(c) (i) We cannot use carbon to obtain sodium from sodium oxide. Why?
(ii) State the reaction taking place at cathode and anode during electrolytic reduction of sodium chloride.

10 Class Science Pre Board – Question: 38.

All living organisms have ability to detect changes in external as well as internal environment and to respond and react appropriately to these changes. Such an ability of organisms is called irritability. The changes in the environment are called stimuli and the organs that detect them are responsive. The response to the stimulus may be carried out by the individual cell, tissue, organs or organ system. The movements shown in response to any stimulus are definite, highly controlled and coordinated. Various organs work in full cooperation and provide a proper reaction for the stimulus and this is called coordination. Coordination in animals is brought about by the nervous and endocrine systems. In plants it is brought about only by chemicals.

1. What are sensory and motor neurons?
2. How is brain protected from injury and shock?
3. In a neuron cell, how is electric impulse created and transmitted?

OR

1. What is the feedback mechanism of hormone regulation? Take the example of insulin to explain this process.

10 Class Science Pre Board – Question: 39. Shefali and Shikha took 3 wires of different dimensions built of same metal ‘X’, as shown in the figure:

They found the resistance of Wire 1 to be 5 Ii using Ohm’s law set up.

1. What will be the resistance of (a) Wire 2 and (b) Wire 3.
2. Which of the 3 wires will have highest resistivity and Why?
3. If wire 1 and wire 2 are connected in series across a 10V battery, what will be the current drawn from the battery?

OR

1. If wire 1 and wire 2 are connected in parallel across a 10V battery, what will be the current drawn from the battery?