Q1
mcq
1 mark
In order to balance the following chemical equation, the values of $a$, $b$, $c$ and $d$ respectively are:
$a\, \text{Pb(NO}_3\text{)}_2 \xrightarrow{heat} b\, \text{PbO} + c\, \text{NO}_2 + d\, \text{O}_2$
- A. 2, 4, 2, 1
- B. 2, 2, 4, 1
- C. 2, 2, 1, 4
- D. 2, 2, 3, 4
Solution hidden
Log in to view solution →
Q2
mcq
1 mark
Choose the chemical equation of a displacement reaction:
- A. $\text{Na}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{NaCl}$
- B. $2\text{NaOH} + \text{H}_2\text{SO}_4 \rightarrow \text{Na}_2\text{SO}_4 + 2\text{H}_2\text{O}$
- C. $\text{Fe}_2\text{O}_3 + \text{Al} \rightarrow \text{Al}_2\text{O}_3 + 2\text{Fe}$
- D. $2\text{FeSO}_4 \rightarrow \text{Fe}_2\text{O}_3 + \text{SO}_2 + \text{SO}_3$
Solution hidden
Log in to view solution →
Q3
mcq
1 mark
Choose the pair of natural indicators:
- A. Litmus and turmeric
- B. Phenolphthalein and litmus
- C. Turmeric and phenolphthalein
- D. Turmeric and litmus
Solution hidden
Log in to view solution →
Q8
mcq
Select a pair of plant hormones from the following:
- A. Cytokinin and Insulin
- B. Gibberellin and Adrenaline
- C. Abscisic acid and Adrenaline
- D. Auxin and Abscisic acid
Solution hidden
Log in to view solution →
Q9
mcq
Select from the following the part/parts of a flower which attracts/attract insects for pollination:
- A. Petals only
- B. Sepals only
- C. Anther and Stigma
- D. Petals and Sepals
Solution hidden
Log in to view solution →
Q10
mcq
The part of human brain which controls muscular coordination is:
- A. medulla
- B. pons
- C. cerebrum
- D. cerebellum
Solution hidden
Log in to view solution →
Q11
mcq
The direction of magnetic field produced around a current carrying straight conductor is determined by using:
- A. Fleming’s left hand rule
- B. Left hand thumb rule
- C. Right hand thumb rule
- D. Fleming’s right hand rule
Solution hidden
Log in to view solution →
Q12
mcq
In a cross between two tall pea plants a few dwarf pea plants were also obtained in F1 generation. It is possible only if the gene combination of the parental plants is:
- A. TT and Tt
- B. TT and tt
- C. Tt and tt
- D. Tt and Tt
Solution hidden
Log in to view solution →
Q17
mcq
Assertion (A) : Magnetic field lines never intersect each other.
Reason (R) : If two field lines intersect each other at a point then it would mean that at the point of intersection the resultant field has two directions, which is not possible.
- A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- C. Assertion (A) is true, but Reason (R) is false.
- D. Assertion (A) is false, but Reason (R) is true.
Solution hidden
Log in to view solution →
Q18
mcq
Assertion (A) : In humans, males play an important role in determining the sex of a child.
Reason (R) : Males have two ‘X’ chromosomes.
- A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- C. Assertion (A) is true, but Reason (R) is false.
- D. Assertion (A) is false, but Reason (R) is true.
Solution hidden
Log in to view solution →
Q19
mcq
Assertion (A) : Calcium oxide is an amphoteric oxide.
Reason (R) : Metal oxides which react with both acids as well as bases to form salt and water are called amphoteric oxides.
- A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- C. Assertion (A) is true, but Reason (R) is false.
- D. Assertion (A) is false, but Reason (R) is true.
Solution hidden
Log in to view solution →
Q20
mcq
Assertion (A) : In humans, the inner lining of the small intestine has finger-like projections called villi which are richly supplied with blood vessels.
Reason (R) : Villi increase the surface area for the absorption of digested food.
- A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- C. Assertion (A) is true, but Reason (R) is false.
- D. Assertion (A) is false, but Reason (R) is true.
Solution hidden
Log in to view solution →
Q21
short answer
2 marks
Ozone, although a deadly poison, performs an essential function for the life on the earth. Justify this statement.
Solution hidden
Log in to view solution →
Q22
short answer
2 marks
(a) Write the chemical name and molecular formula of Plaster of Paris. Why should it be stored in a moisture proof container ?
OR
(b) What is a neutralisation reaction ? Write the chemical equation for a neutralisation reaction and write the name of the salt produced.
Solution hidden
Log in to view solution →
Q23
short answer
2 marks
Write two roles each of (i) bile juice and bile salts and (ii) pancreatic enzymes in the process of digestion.
Solution hidden
Log in to view solution →
Q24
short answer
2 marks
What are plant hormones ? Name one plant hormone each responsible for (i) phototropism and (ii) promotion of cell division.
Solution hidden
Log in to view solution →
Q25
short answer
2 marks
(a) The far point of a defective eye is nearer than infinity.
(i) Identify the defect of vision.
(ii) List two possible causes responsible for this defect.
(iii) Name the type of lens (converging/diverging) used for the correction of this defect.
OR
(b) “The colour of the clear sky from the earth appears blue but the sky appears dark to the passengers flying at very high altitudes.” Explain.
Solution hidden
Log in to view solution →
Q26
short answer
2 marks
(a) What is vegetative propagation ? List its two advantages.
OR
(b) List two distinguishing features between sexual reproduction and asexual reproduction.
Solution hidden
Log in to view solution →
Q27
short answer
3 marks
Consider the following salts :
(i) XCl (ii) NH$_4$Y (iii) ZCO$_3$
Answer the following questions giving reason in each case.
(a) If ‘X’ is sodium, what is the pH of XCl ?
(b) If ‘Y’ is sulphate, what colour would the aqueous solution of NH$_4$Y give when a few drops of universal indicator are added to it ?
(c) If ‘Z’ is calcium, what would be the change in colour in blue litmus paper when a drop of ZCO$_3$ is poured on it ?
Solution hidden
Log in to view solution →
Q28
short answer
3 marks
In the electrolysis of acidulated water
(a) Name the gas collected at the (i) cathode and (ii) anode.
(b) Why is the volume of one gas collected at one electrode two times the gas collected at the other electrode ?
(c) Write the method of testing of any one of the gases evolved in this case.
Solution hidden
Log in to view solution →
Q29
short answer
3 marks
(a) (i) List any two characteristics of lungs which make them an efficient respiratory system.
(ii) Name the part of human respiratory system :
(1) where air is filtered by fine hair and mucus lining.
(2) which separates chest cavity from abdominal cavity.
(3) which has balloon like structures where exchange of gases takes place.
(4) two large air passages which connect trachea to lungs.
Solution hidden
Log in to view solution →
Q30
short answer
3 marks
Explain with the help of a terrestrial food chain how some harmful chemicals enter our bodies through the food chain. Why is the concentration of these harmful chemicals found to be maximum in human beings ?
Solution hidden
Log in to view solution →
Q31
short answer
3 marks
(a) A convex lens of focal length 20 cm is used to focus the image of an object of height 5 cm. If the object distance is 30 cm, find using the lens formula (i) image distance and (ii) image height.
OR
(b) Define the power of a lens. The focal length of a lens is +25 cm. Determine the nature of this lens (converging/diverging). If an object is placed at a distance of 50 cm from the optical centre of this lens, list two characteristics of the image formed in this case.
Solution hidden
Log in to view solution →
Q31
short answer
3 marks
A student has focussed the image of an object of height 5 cm on a screen using a convex lens of focal length 20 cm. If the object distance is 30 cm find, using lens formula, the (i) image distance and (ii) height of the image produced.
Solution hidden
Log in to view solution →
Q31
short answer
3 marks
Define power of a lens. The focal length of a lens is + 25 cm. Determine its nature (converging/diverging) and calculate its power. If an object is placed at a distance of 50 cm from the optical centre of this lens, list two properties of the image formed in this case.
Solution hidden
Log in to view solution →
Q31
short answer
5 marks
If alcohol is X and carboxylic acid is Y, then (1) what happens when X and Y react in the presence of an acid catalyst? Write chemical equation for the reaction. (2) what happens when X is heated in excess of conc. sulphuric acid at 443 K? Write the role of conc. sulphuric acid in the reaction.
Solution hidden
Log in to view solution →
Q32
short answer
3 marks
(a) Define dispersion of white light. Through a glass prism, mention the colour of light that bends (i) least and (ii) most. Also explain the reason for the dispersion of a narrow beam of white light through a glass prism.
OR
(b) What is a rainbow? Write the sequence of light phenomena involved in the formation of a rainbow. List two necessary conditions for observing a rainbow.
Solution hidden
Log in to view solution →
Q32
short answer
3 marks
Define the term dispersion of white light. State the colour of light which bends (i) the least, (ii) the most, while passing through a glass prism. Also, state the cause of dispersion of a narrow beam of white light when it passes through a prism.
Solution hidden
Log in to view solution →
Q32
short answer
3 marks
When and where does a rainbow appear in the sky ? Write sequence-wise the phenomena of light responsible for the formation of a rainbow. List two essential conditions for observing a rainbow.
Solution hidden
Log in to view solution →
Q33
short answer
How is the type of current used in household supply different from the current given by a battery of dry cells ?
Solution hidden
Log in to view solution →
Q33
short answer
Which one of the two currents mentioned above in (a) is considered to be more advantageous for the long distance transmission of electric power and why ?
Solution hidden
Log in to view solution →
Q33
short answer
3 marks
How does the electric fuse prevent the electric circuit and the appliances from a possible damage due to short circuiting ?
Solution hidden
Log in to view solution →
Q34
short answer
5 marks
(i) Write the name and formula of (1) an alcohol and (2) a carboxylic acid having two carbon atoms.
(ii) If alcohol is X and carboxylic acid is Y, then
(1) what happens when X and Y react in the presence of an acid catalyst ? Write chemical equation for the reaction.
(2) what happens when X is heated in excess of conc. sulphuric acid at 443 K ? Write the role of conc. sulphuric acid in the reaction.
Solution hidden
Log in to view solution →
Q35
short answer
5 marks
(a) (i) Write the function of the following parts of a bisexual flower : (1) stigma (2) pollen tube and (3) anther (ii) Name the (1) future shoot and (2) future root of a germinating seed. (iii) Name the parts of the flower that develop into (1) seed and (2) fruit after fertilization.
Solution hidden
Log in to view solution →
Q35
short answer
5 marks
(b) (i) Name the organ that produces sperms as well as secretes hormone in human male reproductive system. Name the hormone it secretes and write its function. (ii) Name the part of the human female reproductive system where (i) fertilisation occurs and (ii) implantation of zygote takes place. (iii) Explain how the embryo gets its nourishment inside the mother’s body.
Solution hidden
Log in to view solution →
Q36
short answer
5 marks
(a) List two factors on which the resistance of a conductor in the shape of a straight cylinder depends. Write the relation between resistance (R) and the resistivity (r) of the material of the conductor. Use this relation to obtain the SI unit of resistivity. (b) Resistance of a metal wire of length 1 m is 40 W. If the area of cross-section of the wire is 6·5 ´ 10–8 m2, find the resistivity of the material of the wire.
Solution hidden
Log in to view solution →
Q37
short answer
Alloying is a very good method of improving the properties of metals. Most of the metallic objects (cooking utensils, ornaments, coins, guns, etc.) are made up of alloys. It is because pure metals are generally very soft and have low melting points. For example, iron is the most widely used metal, but it is never used in its pure form to make cooking pans because it is very soft in its purest form, it is corrosive and easily stretches when hot. (a) What is an alloy? (b) Write the constituents of bronze. (c) (i) How is stainless steel made? List two properties in which it
Solution hidden
Log in to view solution →
Q38
short answer
2 marks
(c) (i) List two properties of the image formed due to a concave mirror of focal length $15\ \text{cm}$ in each of the following cases : 2
(1) object distance $20\ \text{cm}$
(2) object distance $10\ \text{cm}$
OR
Solution hidden
Log in to view solution →
Q39
short answer
2 marks
(c) (ii) A $3\ \text{cm}$ long candle flame is placed in front of a concave mirror. If the distance between the pole and the candle flame is $40\ \text{cm}$ and the image is formed at the same place where the candle flame is located, find the 2
(1) focal length of the mirror, and
(2) magnification of the image formed with sign as per the New Cartesian Sign Convention.
Solution hidden
Log in to view solution →