SCIENCE JULY 2015 PAPER ONE

NOTE: (i) Draw well - labelled diagrams wherever necessary.
(ii) All questions are compulsory.
(iii) Students should write the answers of questions in sequence.

Q. 1. A. (1) Fill in the blanks [2]

(1) Very fine particles mainly scatter _____________ light. (blue)

(2) 1 mA = __________________ A.  (10-3A)


(2) Match the column ‘A’ with column ‘B’. [3]
Column ‘A’
Column ‘B’
(1) Eka - boron
(a) Germanium
(2) Eka - Aluminium
(b) Scandium
(3) Eka - Silicon
(c) Gallium


(B) Choose the correct alternative and rewrite the following: [5]

(1) Mirror used by a dental surgeon is ______________.
(a) plane
(b) convex
(c) concave
(d) convex and concave

(2) What will happen to the curent passing through a resistance, if the potential difference across it is doubled and the resistance is halved?
(a) remains unchanged
(b) becomes double
(c) becomes half
(d) becomes four times

(3) You are given three equal resistances. In how many combinations can they be arranged?

(a) Three
(b) Four
(c) Five
(d) Two

(4) Inside water, an air bubble behaves _______.
(a) always like a flat plate
(b) always like a concave lens
(c) always like a convex lens
(d) always like a concave mirror

(5) A glass slab is placed in the path of convergent light. The point of convergence of light
(a) moves away from slab
(b) moves towards the slab
(c) remains at the same point
(d) undergoes lateral shift


Q. II. Answer the following questions. (any five)  [5 x 2 = 10]

i. State Dobereiner’s Triads giving one example.


ii. Edible oil is not allowed to stand for a long time in an iron or tin container. Give reasons.



iii. An electric iron rated 750 W is operated for 2 hours/day. How much energy is consumed by the electric iron for 30 days?


iv. Differentiate between conductors and insulators (any two points).




v. Give four uses of sodium carbonate (washing soda).



vi. Draw a labelled diagram: Dispersion of light through a prism.





Q. III. Answer the following questions. (any five): [5 x 3 = 15]

i. If sodium chloride is added to silver nitrate solution:
a. which precipitate is formed?
b. name the type of reaction.
c. write the chemical equation.


ii. Define:
a. Chemical combination reaction
b. Endothermic reaction
c. Oxidation reaction


iii. Give the uses of a concave mirror.




iv. Name any six domestic appliances based on the heating effect of electric current.


v. Explain: ‘How is a rainbow formed’?


vi. If an object is placed in front of a convex lens beyond 2F1, then what will be the position, relative size and nature of an image which is formed? Explain with a ray diagram.



Q. IV. Answer any one of the following questions: [5]

i. Explain ‘Electric generator’ with the help of the following points:
a. Diagram of an AC Generator with labelling
b. Principle of an electric generator
c. Function of slip rings
d. Any two uses of a generator.


ii. Write about the sources of noise pollution. Give the impact of noise pollution on human body.