# 10th Science Paper Solutions Set 3 : CBSE Abroad Previous Year 2009

General Instructions:
1. Attempt all questions.
2. There are 30 multiple choice questions in total. Only one of the options in every question is correct.
3. The question paper consists of two sections - Section A and Section B. Each of the 20 questions in Section A carries half mark and each of the 10 questions in Section B carries one mark.
4. 15 minutes additional time will be given to you to read the questions.
Q1 :

While doing an experiment on plotting the temperature vs. time graph of hot water as it cools, we can get a good graph

(1) only by noting the temperature of hot water every 30 seconds throughout.

(2) only by noting the temperature of hot water every 1 minute throughout.

(3) by noting the temperature of hot water every 1 minute to start with and every 2 minutes later on.

(4) by noting the temperature of hot water every 2 minutes to start with and every 1 minute later on.

We can get a good graph when readings are taken after short intervals of time. Therefore, we can get a good graph by noting the temperature of hot water every 30 seconds throughout.

Q2 :

In an experiment on determining the velocity of a pulse propagating through a stretched string, the stop-watch should be started and stopped at instants corresponding to the ones shown in

(1) Figure 1 and Figure 2

(2) Figure 1 and Figure 3

(3) Figure 2 and Figure 1

(4) Figure 2 and Figure 3

In figure 1, the disturbance is just started in the string, and in figure 3, it finally reaches the rigid support. Therefore, to measure the velocity of the propagation of the pulse, the stop watch should be started and stopped at the instants corresponding to figures 1and 3respectively.

Q3 :

The diagrams given above, show tissues of some plants and/or animals. The diagrams showing animal tissues are

(1) I and III

(2) II and III

(3) I and IV

(4) II and IV

Diagram II shows the muscle tissue and diagramIVshows the neural tissue.

DiagramsI and III have cells with a cell wall and a large-sized vacuole. Hence, these are plant tissues.

Q4 :

The animal whose figure is given below is included in its phylum because of the part labelled as

(1) I

(2) II

(3) III

(4) IV

Q5 :

A student mixed some acetic acid with water. He would have observed the solution formed as

(1) Green and transparent

(2) Pink and opaque

(3) Yellow and transparent

(4) Colourless and transparent

Q6 :

While performing an experiment on determining the focal length of a convex lens a student obtains a sharp inverted image of the laboratory window grills on the screen and measures the distance dbetween the screen and the lens. She then repeats the experiment and takes a distant tree as the object in the second case. In order to get a sharp image on the screen, she will now need to move the screen

(1) slightly nearer to the lens

(2) slightly farther away from the lens

(3) very close to the lens

(4) very far away from the lens

Q7 :

Out of the two circuits shown here, the two resistors R1and R2have been correctly connected in series in

(1) circuit A only

(2) circuit B only

(3) both circuits A and B

(4) neither of the two circuits

Q8 :

In an experiment on studying the dependence of the current (I), flowing through a given resistor on the potential difference (V) applied across it, a student is to change the value of the current. For doing this, he can change the

(1) number of cells used or by setting the battery eliminator

(2) resistor itself

(3) ammeter used in the circuit

(4) voltmeter used in the circuit

Q9 :

A student by mistake mixed sulphur powder with iron filings. The following techniques were suggested to him to separate the sulphur from the mixture, out of which he has to choose one:

A. dissolving in carbon disulphide, filtration, evaporation

B. dissolving in water at room temperature and filtration

C. dissolving in hot water, filtration and evaporation

D. dissolving in ice cold water and filtration

The correct technique is

(1) A

(2) B

(3) C

(4) D

Q10 :

Four students did their experiment on studying the cooling caused by evaporation of alcohol and recorded the following as their observations:

A. After dipping in alcohol, the cotton plug absorbs alcohol and becomes pale blue.

B. After attaching the cotton plug dipped in alcohol to the bulb of the thermometer and exposing the thermometer to air, the temperature starts falling

C. After evaporation is complete, temperature starts increasing

D. Tiny bubbles of alcohol escape from the surface of the cotton plug.

The correct observations are those of students

(1) B and D

(2) B and C

(3) A and C

(4) A and D

Q11 :

A student does the labelling, indicated below, for the apparatus used for separating a mixture of camphor and sand

The parts that have been incorrectly labelled are

(1) I, II, VII

(2) III, IV, V

(3) II, III, VI

(4) VII, V, I

Q12 :

The figure given below shows plant cells which had been placed in

(1) an isotonic solution

(2) a hypertonic solution

(3) an isosmotic solution

(4) a hypotonic solution

Q13 :

On putting few drops of an unknown liquid on pH strip, the colour of pH strip changed to green. The liquid taken is likely to be

(1) water

(2) dilute hydrochloric acid

(3) lemon juice

(4) dilute sodium hydroxide solution

Q14 :

The following set-up is used for the preparation of sulphur dioxide gas

For this set-up identify the only correct statement from the following:

(1) Tip of the delivery tube should not dip in the sulphuric acid

(2) Tip of the thistle funnel should not dip in the sulphuric acid

(3) Burner is not required

(4) Wire gauze is not required

Q15 :

The chemical required in the experiment to show that carbon dioxide gas is released during respiration, is

(1) Potassium bicarbonate

(2) Potassium dichromate

(3) Potassium permanganate

(4) Potassium hydroxide

Q16 :

The formula used for calculating the percent water absorbed, when pre-weighed dry raisins are placed in water for two hours, and weighed again is

(1)

(2)

(3)

(4)

Q17 :

To prepare a good temporary mount of the petunia leaf peel showing many stomata, the student has to get the peel from the

(1) tip of the leaf

(2) upper surface of the leaf

(3) lower surface of the leaf

(4) point of attachment of the leaf to its petiole

Q18 :

Which of the following experimental arrangements is correct for determination of melting point of ice?

(1) I

(2) II

(3) III

(4) IV

Q19 :

A student is given an iron cube of side 1 cm, a measuring cylinder of range 100 mL and least count 1 mL and a spring balance of range 100 gwt and least count 1 gwt. He can use these to measure

(1) both the mass and the volume of the given iron cube

(2) neither the mass nor the volume of the given iron cube

(3) only the mass of the given iron cube but not its volume

(4) only the volume of the given iron cube but not its mass

Q20 :

Three students are given three identical solids. They measure the volume of water overflowing out of the three overflow cans as shown. When they dip these solids completely in water the volumes of overflow water are denoted as VA, VB, and VC.

It will be found that

(1) VA= VB= VC

(2) VA= VB≠ VC

(3) VA≠ VB= VC

(4) VC= VA≠ VB

Q21 :

A teacher gave an impure sample of alum containing fine sand as impurity to a student. He asked him to recover pure alum from this sample. The correct procedure to be followed would be to

(1) dissolve the impure sample of alum in water, filter and evaporate the filtrate

(2) dissolve the impure sample of alum in alcohol and filter

(3) move a magnet over the impure sample of alum

(4) dissolve the impure sample of alum in carbon disulphide, filter and evaporate the filtrate to dryness.

Q22 :

To prepare a slide of cells like those shown above, the cells must have been obtained by

(1) taking an onion peel

(2) scraping the uppermost inside lining of the cheek

(3) squashing tissue from the spinal cord of frog

(4) crushing the thigh muscles of a cockroach

Q23 :

A student traces the path of a ray of light passing through rectangular glass slab for three different values of angle of incidence (i), namely 30°, 45°, 60°. He produces the incident ray and measures the perpendicular distance, l, between the produced incident ray and the emergent ray

He will observe that

(1) ‘l’ keeps on increasing with increase in angle of incidence

(2) ‘l’ keeps on decreasing with increase in angle of incidence

(3) ‘l’ remains the same with three angles of incidence

(4) ‘l’ is maximum for i = 45°and is less than this value both for i= 30°and for i = 60°

Q24 :

A student, using the same two resistors, battery, ammeter and voltmeter, sets up two circuits, connecting the two resistors, first in series and then in parallel. If the ammeter and voltmeter readings in the two cases, are (I1, I2) and (V1, V2) respectively, he is likely to observe that

(1) I1= I2but V1≠ V2

(2) I1< I2but V1= V2

(3) I1> I2but V1= V2

(4) I1= I2and V1= V2

Q25 :

Two students, while doing their experiments on verifying the laws of reflection of sound are provided with the following choices:

(i) using a narrow tube or a wide tube

(ii) using a faint source or a strong source of sound

The difference between the measured values of the angle of incidence and angle of reflection is likely to be larger for the student using the combination of

(1) narrow tube and faint source

(2) narrow tube and strong source

(3) wide tube and faint source

(4) wide tube and strong source

Q26 :

I II

Of the two plants I and II, whose figures are given above,

(1) both are pteridophytes because both possess roots and leaves

(2) both are angiosperms because both possess roots and leaves

(3) II is a pteridophyte as its leaves resemble those of the fern and may bear sori

(4) II is an angiosperm as it bears flowers and fruits.

Q27 :

A student took two tubes containing 2 mL of dilute hydrochloric acid and added zinc granules to test tube (A) and solid sodium carbonate to test tube (B) as shown below:

The correct observation would be

(1) Rapid reaction in both the test tubes

(2) Slow reaction in (A) and rapid reaction in (B)

(3) Rapid reaction in (A) but a slow reaction in (B)

(4) No reaction in any of the test tubes

Q28 :

A student took four test tubes I, II, III, and IV containing aluminium sulphate, copper sulphate, ferrous sulphate and zinc sulphate solution respectively. He placed an iron strip in each of them. He found a brown deposit formed in test tube

(1) I

(2) II

(3) III

(4) IV

Q29 :

The two diagrams, given below, aim to show the sequence of events of the binary fission in amoeba and budding in yeast.

Binary fission in Amoeba

Budding in yeast

The correct sequences of events in the two diagrams respectively are

(1) (I, II, III, IV) and (V, VI, VII)

(2) (IV, III, II, I) and (VII, VI, V)

(3) (II, III, I, IV) and (VI, V, VII)

(4) (III, I, II, IV) and (VI, VII, V)

Q30 :

A star-shaped black paper was used to cover a leaf in a destarched plant as shown below. The plant was left in sunlight for four hours and then the leaf was plucked, black paper, removed and tested for the presence of starch. The areas which turned blue-black when iodine solution was added were.

(1) I, II, III, IV

(2) I, III, IV

(3) Only II

(4) Only IV