Board Paper of Class 10 2014 Science - Solutions
Note:
1. Use the same answer-sheet for Section A and Section B.
2. Draw well-labelled diagrams wherever necessary.
3. All questions are compulsory.
4. Students should write the answers of questions in sequence.
1. Use the same answer-sheet for Section A and Section B.
2. Draw well-labelled diagrams wherever necessary.
3. All questions are compulsory.
4. Students should write the answers of questions in sequence.
- Question 1
(A) (a) Rewrite the following statements with suitable words in the blanks:
i. Very fine particles mainly scatter ………… coloured light.
ii. The element eka-silicon in Mendeleev’s periodic table isknown as ………… in the modern periodic table.iii. Sodium or potassium salt of higher fatty acid is termed …………[3] (b) State whether the following statements are True or False:
i. CuSO4(aq) + Zn(s) → ZnSO4(aq) + Cu(s) is an example of a decomposition reaction.
ii. Magnetic lines of force are closed continuous curves.[2] (B) Rewrite the following statements by selecting the correct options: [5] i The reddish brown deposit formed on iron nails kept in a solution of copper sulphate is
(a) Cu2O
(b) Cu
(c) CuO
(d) CuSii What will be the change in the current if the potential difference is kept constant and the resistance of the circuit is made four times?
(a) It will remain unchanged.
(b) It will become four times.
(c) It will become one-fourth.
(d) It will become half.iii. A ray of light strikes the glass slab at an angle of 50°. What is the angle of incidence?
(a) 50°
(b) 25°
(c) 40°
(d) 100°iv From which plant is litmus paper or litmus solution obtained?
(a) Moss
(b) Rose
(c) Hibiscus
(d) Lichenv If the equivalent resistance is to be increased, then the number of resistances should be connected in
(a) Series
(b) Parallel
(c) Mixed arrangement
(d) None of the above
- Question 2
Answer any five of the following: [10] (i) Elements in the same group show the same valency.
Give scientific reason.(ii) Find the resistance of a conductor if 0.24 A current is passing through it and a potential difference of 24 V is applied across it. (iii) Differentiate between primary pollutants and secondary pollutants. (iv) Write the electronic configuration of K and Ne. (v) State Fleming’s right-hand rule. (vi) Write a short note on dispersion of light.
- Question 3
Answer any five of the following: [15] (i) State three differences between direct current and alternating current. (ii) After you have dinner tonight, wash your own plates with soap/detergent. a. What colour change is observed when soap/detergent is applied?
b. Name the type of reaction and explain it.(iii) Methyl orange is used as an indicator. It shows colour change in acid, base and neutral substance. Tabulate your result as follows: Indicator Colour change Inference Methyl
OrangeNo change …………………. …………………. Acid Yellow …………………. (iv) Given below is a diagram showing a defect of the human eye. Study it and answer the following questions:
(a) Name the defect shown in the figure.
(b) Give two possible reasons for this defect of the eye in human being.
(c) Name the type of lens used to correct the eye defect.(v) State three effects of radioactive pollution. (vi) Define refraction and state the laws of refraction.
- Question 4
Attempt any one of the following: [5] (i) With a neat labelled diagram and derive the equation for three resistances connected in parallel. (ii) With the help of an appropriate ray diagram, state the sign conventions for reflection by a spherical mirror.