March 2015 Science and Technology Board Paper with Solution

March 2015 Science and Technology Board Paper with Solution

1. A. a. Read the following statements with suitable words in the blanks:

i. The device used for producing electric current is called a ________________ (Electric Generator)

ii. ____________ the second layer of the atmosphere reaches 48 km above the earth’s surface. (Stratosphere)

b. Rewrite the following table so as to match the second column with the first column:

Column A	column B
i. eosin	1. losing hydrogen
ii. oxidation	2. synthetic indicator
	3. losing oxygen
	4. natural indicator

c. Give the molecular formula of bleaching powder.

Ans. CaOCl₂

(B) Rewrite the following statements by selecting the correct options:

1. When phenolphthalein is added to NaOH, the colour of the solution will become _______ (pink)

a. colourless

b. red

c. pink

d. yellow

2. If the potential difference across the ends of a conductor is 220 V and the resistance of the conductor is 44 Ω (ohm), then the current flowing through is _______________(5 A)

a. 0.2 A

b. 0.5 A

c. 2 A

d. 5 A

3. 1 A = ______________ mA (10^-3 )

a. 10²

b. 10³

c. 10^-3

d. 10^-6

4.  The distance between principal focus and optical centre of the lens is ______________  (Focal length)

a. diameter

b. focal length

c. principal axis

d. optical centre

5. When rays of light are incident on a glass slab, then the incident ray and emergent ray are __________ to each other.  (parallel)

a. perpendicular

b. parallel

c. opposite

d. concurrent.

Section B

5. A. a. Find the correlation in the given pair and rewrite the answer:

1. Tinning : Tin ∷ Galvanizing: ______________ (iron)

2. Mammals: _______________ ∷ Amphibia : Fishes (Reptiles)

b. State True or False:

1. Solar water – heater works on renewable energy system. (True)

2. In human beings the blood goes to the heart in one cycle once. (False)

3. In frog, thyroid secretion stimulates the metamorphosis from tadpole to adult frog. (True)

(B) Rewrite the following statements by selecting the correct options:

1. The molecular formula of acetic acid is ______________ [CH₃COOH]

a. CH₃COOH

b. CH₃ – CH₃

c. C₆H₆

d. C₂H₄

2. Carbon dioxide enters into the leaves through tiny pores present on the surface of the leaf called ________ [stomata]

a. chlorophyll

b. chloroplast

c. stomata

d. epidermis

3. _________________ is the solution in blue in colour.  (CuSO₄)

a. CuSO₄

b. FeSO₄

c. ZnSO₄

d. Al₂(SO_4­­­)₃

4. Yeast reproduced by _______________ (budding)

a. Spore formation

b. multiple fission

c. fragmentation

d. budding

5. Raisins put in water absorb water by the process of ____________ (osmosis)

a. diffusion

b. osmosis

c. transpiration

d. excretion