Q1
mcq
1 mark
In the following case(s) the combination reaction occurs in:
- A. Only III
- B. Only IV
- C. II and III
- D. I, III and IV
Solution hidden
Log in to view solution →
Q7
mcq
1 mark
Select the correct statement from the following about the reaction: $\mathrm{CuO + H_2 \rightarrow Cu + H_2O}$
- A. $\mathrm{CuO}$ is getting oxidised and $\mathrm{H_2}$ is getting reduced.
- B. $\mathrm{H_2}$ is getting oxidised and $\mathrm{CuO}$ is getting reduced.
- C. $\mathrm{CuO}$ is a reducing agent.
- D. $\mathrm{H_2}$ is an oxidising agent.
Solution hidden
Log in to view solution →
Q8
mcq
In the human respiratory system, the path taken by air when we breathe in is :
- A. Nostrils Larynx Trachea Pharynx Alveoli
- B. Nostrils Trachea Larynx Pharynx Alveoli
- C. Nostrils Pharynx Larynx Trachea Alveoli
- D. Nostrils Larynx Pharynx Trachea Alveoli
Solution hidden
Log in to view solution →
Q9
mcq
1 mark
A doctor advised a person to take an injection of insulin because:
- A. his heart was beating slowly.
- B. his blood pressure was low.
- C. he was looking short in height.
- D. his pancreas was not secreting the required hormone in proper amounts.
Solution hidden
Log in to view solution →
Q10
mcq
1 mark
The movement of sunflowers is in response to a stimulus such as:
- A. gravity
- B. chemicals
- C. day or night
- D. water
Solution hidden
Log in to view solution →
Q11
mcq
1 mark
In bread mould, the structures labelled A and B respectively are:
- A. hyphae and spore
- B. root and sporangium
- C. hyphae and sporangium
- D. root and spores
Solution hidden
Log in to view solution →
Q12
mcq
In plants, waste products like resins and gums are stored in :
- A. leaves that fall off
- B. old xylem
- C. phloem
- D. cellular vacuoles
Solution hidden
Log in to view solution →
Q13
mcq
The image formed by a concave mirror of focal length 50 cm is real and of magnification $-1$. In this case the distance between the object and its own image is :
- A. 50 cm
- B. 100 cm
- C. 200 cm
- D. Zero
Solution hidden
Log in to view solution →
Q14
mcq
When we connect too many electrical appliances to a single socket in a circuit having a fixed value of current rating :
- A. the total resistance of the circuit increases.
- B. the current drawn from the source decreases.
- C. the current increases beyond the rated value.
- D. each appliance starts drawing more and more current from the source.
Solution hidden
Log in to view solution →
Q15
mcq
Consider the following statements :
I. Every step in a food chain is called a trophic level.
II. Decomposers convert complex inorganic matter in dead remains of organisms into simple substances that go into the soil.
III. In a food chain, energy level increases from lower trophic level to higher trophic level.
IV. Linkages between various food chains constitute a food web.
The correct statements is/are :
- A. I only
- B. I and IV
- C. I, II and IV
- D. II and IV
Solution hidden
Log in to view solution →
Q15
short answer
2 marks
Name the parts of the nervous system which are involved in the following activities: (i) Maintaining body posture (ii) Salivation (iii) Hunger (iv) Answering a question
Solution hidden
Log in to view solution →
Q16
mcq
Biomagnification refers to the increase in the :
- A. body weight of an organism.
- B. growth of phytoplanktons.
- C. amount of harmful chemicals in the successive trophic levels of a food chain.
- D. number of plants and animals in an area.
Solution hidden
Log in to view solution →
Q21
short answer
2 marks
Define the terms ductility and malleability. Name an element which exhibits both of these properties giving justification for your answer.
Solution hidden
Log in to view solution →
Q22
short answer
2 marks
List two ways due to which variations arise in a population. State the importance of variation.
Solution hidden
Log in to view solution →
Q23
short answer
2 marks
In the diagram given below, name the labelled parts X and Y. Mention one function for each.
Solution hidden
Log in to view solution →
Q23
short answer
3 marks
Name a part of the flower which (i) persists even after a fruit is formed, (ii) attracts insects for pollination, (iii) produces pollen grains and (iv) changes into seed after fertilisation.
Solution hidden
Log in to view solution →
Q24
short answer
2 marks
Draw a labelled ray diagram to show the formation of image due to a concave mirror when an object is placed between its pole and principal focus.
Solution hidden
Log in to view solution →
Q24
short answer
3 marks
After pollination, how does a male germ cell reach the ovary? Mention the significance of this event.
Solution hidden
Log in to view solution →
Q25
long answer
2 marks
(a) Draw a ray diagram to show the formation of a rainbow in the sky. Mark on the diagram three points A, B and C as given below:
A – where dispersion of light occurs
B – where internal reflection of dispersed light occurs
C – where refraction of dispersed light occurs
OR
(b) Name the muscles present in the human eye which enable it to focus on objects at varied distances (i.e., distant as well as nearby objects). Explain how it happens.
Solution hidden
Log in to view solution →
Q25
short answer
3 marks
A plant having blue coloured flowers (BB) is crossed with a plant having white coloured flowers (bb):
(i) Name the term used for the trait, which is observed in F1 generation. Give its gene combination.
Solution hidden
Log in to view solution →
Q26
short answer
2 marks
“A vegetarian food habit helps in getting more energy.” Justify the statement.
Solution hidden
Log in to view solution →
Q26
short answer
3 marks
If the plants obtained in F1 generation are self-pollinated, write the percentage of (i) plants with flowers of blue colour, and (ii) plants with flowers of white colour in F2 generation. What did the reappearance of plants with white coloured flowers in F2 generation indicate?
Solution hidden
Log in to view solution →
Q27
short answer
3 marks
(a) Write a chemical equation for the reaction in which change in colour is observed when a metal is kept immersed in a salt solution of another metal.
(b) When hydrogen gas is passed over heated copper(II) oxide, copper and steam are formed. Write the balanced chemical equation with physical states for this reaction. State what kind of chemical reaction is this.
Solution hidden
Log in to view solution →
Q28
short answer
3 marks
(a) What is meant by the term pH of a solution? The pH of rain water collected from two cities ‘A’ and ‘B’ was found to be 6.1 and 5.3 respectively. The water of which city is more acidic? Justify your answer. State with reason what would happen to the aquatic life of a pond in which the rain water of city ‘B’ flows.
OR
(b) (i) Identify the acid and the base from which the following salts are obtained:
(I) Sodium chloride
(II) Ammonium sulphate
(ii) Write the nature, acidic/basic/neutral, of each of the above mentioned salts, giving reason for your answer.
Solution hidden
Log in to view solution →
Q29
short answer
3 marks
(a) Name a part of the flower which (i) persists even after a fruit is formed, (ii) attracts insects for pollination, (iii) produces pollen grains and (iv) changes into seed after fertilisation.
(b) After pollination, how does a male germ cell reach the ovary? Mention the significance of this event.
Solution hidden
Log in to view solution →
Q29
long answer
5 marks
Write electronic configurations of two elements X (At. no. 12) and Y (At. no. 17). Show the formation of ionic compound when X and Y combine with each other. Write the name and formula of the compound formed. State what would happen if electric current is passed through the aqueous solution of this compound. Name the ion that will reach at (i) cathode, and (ii) anode.
Solution hidden
Log in to view solution →
Q30
short answer
3 marks
A plant having blue coloured flowers (BB) is crossed with a plant having white coloured flowers (bb):
(a) Name the term used for the trait, which is observed in F1 generation. Give its gene combination.
(b) If the plants obtained in F1 generation are self-pollinated, write the percentage of (i) plants with flowers of blue colour, and (ii) plants with flowers of white colour in F2 generation. What did the reappearance of plants with white coloured flowers in F2 generation indicate?
Solution hidden
Log in to view solution →
Q30
short answer
5 marks
Write the name of two metals of moderate reactivity. Which one of the two is more reactive? How can this fact be demonstrated experimentally in a school laboratory?
Solution hidden
Log in to view solution →
Q31
short answer
3 marks
In the given circuit when key is closed, determine the following:
(i) Total resistance offered by the three resistors
(ii) Reading of the ammeter
(iii) Reading of the voltmeter
Solution hidden
Log in to view solution →
Q31
short answer
5 marks
Some metals of moderate reactivity are also found in the Earth’s crust in the form of their carbonates. Name the processes involved in the extraction of metal from them, giving chemical equations for the reactions that occur.
Solution hidden
Log in to view solution →
Q32
short answer
5 marks
Study the diagram below of alimentary canal of man and name the parts marked as A, B and C. Write the name of the enzyme present in each labelled part.
Solution hidden
Log in to view solution →
Q33
short answer
3 marks
Draw a ray diagram to show the refraction of a ray of light through a triangular glass prism and mark on it (i) angle of incidence (i), (ii) angle of emergence (e), and (iii) angle of deviation (D). What would happen, if instead of a ray, a beam of white light falls on the prism? Give reason for the phenomenon that occurs in this case.
Solution hidden
Log in to view solution →
Q33
short answer
5 marks
Explain how digested food reaches each and every cell of the body and is utilised.
Solution hidden
Log in to view solution →
Q34
short answer
5 marks
Study the diagram below showing schematic representation of transport and exchange of gases in human heart and name the parts labelled as A, B and C. Mention the function of each part.
Solution hidden
Log in to view solution →
Q35
short answer
5 marks
Explain how separation of right and left side of the heart is useful for birds.
Solution hidden
Log in to view solution →
Q36
short answer
5 marks
Write the relation between the electrical resistivity $r$ and the resistance $R$ of a cylindrical conductor of length $l$ and area of cross-section $A$. Use this relationship to determine the SI unit of $r$.
Solution hidden
Log in to view solution →
Q37
short answer
5 marks
Find the electrical resistivity of the material of a wire of length 120 cm and diameter 0.4 mm. The resistance of this wire is 3 $\Omega$.
Solution hidden
Log in to view solution →
Q37
short answer
2 marks
Ethanol (commonly known as alcohol) is an important carbon compound widely used in industries, hospitals, etc. Because it is a very good solvent, it is used in medicines such as cough syrups, tincture iodine and many tonics. As it is a cleaner fuel, ethanol is used as an additive in petrol in most of the developed countries of the world.
(a) Write the structure of ethanol.
(b) Name the products formed when ethanol burns in sufficient air (oxygen).
(c)(i) State what happens when 5% solution of alkaline potassium permanganate is added to warm ethanol. Draw the structure of the product formed and state the role of 5% solution of alkaline potassium permanganate in the reaction.
Solution hidden
Log in to view solution →
Q38
short answer
5 marks
What is meant by heating effect of electric current? Derive an expression for the amount of heat produced in a conductor of resistance $R$ through which a current $I$ flows for a time $t$.
Solution hidden
Log in to view solution →
Q39
short answer
5 marks
Calculate the amount of heat produced in a conductor of resistance 10 $\Omega$ through which a current of 2 A flows for 100 seconds.
Solution hidden
Log in to view solution →Reading Passage
Ethanol (commonly known as alcohol) is an important carbon compound widely used in industries, hospitals, etc. Because it is a very good solvent, it is used in medicines such as cough syrups, tincture iodine and many tonics. As it is a cleaner fuel, ethanol is used as an additive in petrol in most of the developed countries of the world.
Q41
short answer
1 mark
Name the products formed when ethanol burns in sufficient air (oxygen).
Solution hidden
Log in to view solution →
Q42
short answer
2 marks
State what happens when 5% solution of alkaline potassium permanganate is added to warm ethanol. Draw the structure of the product formed and state the role of 5% solution of alkaline potassium permanganate in the reaction.
Solution hidden
Log in to view solution →
Q44
short answer
1 mark
The image of an object formed by a convex lens of focal length 2 cm is real, inverted and magnified. What is the range of object distance in this case?
Solution hidden
Log in to view solution →
Q45
long answer
2 marks
(i) An object is placed at a distance of 12 cm from the optical centre of a convex lens of focal length 18 cm. Draw a labelled ray diagram to show the formation of image in this case.
Solution hidden
Log in to view solution →
Q46
long answer
2 marks
(ii) The image formed by a convex lens is real, inverted and of the same size as the object. If the distance between the object and the image is 60 cm, determine the focal length of the lens. Give justification for your answer.
Solution hidden
Log in to view solution →