10th Science Paper Solutions Set 1 : CBSE Abroad Previous Year 2005

General Instructions:
(i) The question paper consists of two sections, A and B. You are to attempt both the sections.
(ii) All questions are compulsory.
(iii) There is no overall choice. However, internal choice has been provided.
(iv) All questions of Section A and all questions of Section B are to be attempted separately.
(v) Questions number 1 to 5 in Section A and 21 to 23 in Section B are short answer type questions. These questions carry one mark each.
(vi) Questions number 6 to 10 in Section A and 24 to 25 in Section B are short answer type questions and carry two marks each.
(vii) Questions number 11 to 17 in Section A and 26 to 29 in Section B are also short answer type questions and carry three marks each.
(viii) Questions number 18 to 20 in section A and question number 30 in section B are long answer type questions and carry five marks each.
Q1 :

Why does a large increase in temperature slow down a reaction catalysed by an enzyme?


Answer :

Out of current syllabus

Q2 :

Dry ammonia gas has no action on litmus paper, but a solution of ammonia in water turns red litmus paper blue, why is it so?


Answer :

A solution of ammonia in water results in the formation of ammonium hydroxide (). Ammonium hydroxide is basic in nature and turns red litmus blue.

Q3 :

What is seen to happen when a piece of sodium metal is dropped into water?


Answer :

As soon as a piece of sodium metal is dropped into water, bubbles will come out showing the evolution of a gas. This gas is hydrogen. The reaction that takes place between sodium metal and cold water is given below:

Q4 :

Where will the image be formed by a convex mirror if the object is placed between infinity and the pole of the mirror?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q5 :

Should the heating element of an electric iron be made of iron, silver or nichrome wire?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q6 :

What are the raw materials used in the manufacture of Portland Cement? What is Reinforced Cement Concrete (RCC)?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q7 :

Name the catalyst used in the manufacture of ammonia by Haber’s Process. How is the ammonia formed separated from the other gases?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q8 :

Describe a method for finding out the exact North-South direction at a place using the direction of sunlight.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q9 :

In what S.I. units is the power of lenses stated? A convex lens has a focal length of 50 cm. Calculate its power.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q10 :

Describe a nuclear chain reaction with an example.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q11 :

How did Arrhenius define acids and bases? Choose a strong acid and a weak base from the following substances:

CH3COOH, NH4OH, HC1, KOH


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q12 :

Draw a labelled diagram of the Frasch Process for obtaining sulphur from places deep underground.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q13 :

What are detergents? What change has been made in detergents to make them easily bio-degradable? Explain the cleansing action of detergents.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q14 :

(a) Write a chemical equation to show how ethanol can be converted into ethanoic acid.

(b) Describe the action of ethanoic acid on sodium carbonate solution.

(c) Complete the following reaction equation:

CH3COONa (s) + NaOH (s)

OR

Define the term, ‘fermentation’. Name the enzyme which converts

(i) milk into curd (yogurt)

(ii) cane sugar into glucose and fructose, and

(iii) glucose into ethanol


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q15 :

A steady current is passed for 30 minutes through two voltameters connected in series:

a copper voltameter [Cu cathode in CuSO4 solution], and a silver voltameter [Ag cathode

in AgNO3 solution]. If the mass of copper deposited in the first voltameter is 21.17 g;

calculate the mass of silver deposited on the cathode in the other voltameter.

Given: Relative Atomic mass of Cu = 63.5, Ag = 108.0.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q16 :

What is meant by the combustion of CH4 ? List the three essential requirements for any combustion to take place. Give reasons for the difficulty experienced in burning a piece of wood if (i) it is wet, (ii) it is large in size.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q17 :

State the composition of the three main layers of the earth, centre outwards.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q18 :

Describe with examples the following steps associated with the extraction of metals from their ores:

(i) Froth-floatation process

(ii) Roasting of an ore

(iii) Calcination of an ore

OR

Differentiate between an ‘alloy’ and an ‘amalgam’. How are alloys made? State with examples any two properties in which an alloy may be different from those of its constituents.

Write the constituents and special advantages of:

(i) Stainless steel

(ii) Magnalium


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q19 :

What are ‘simple’ and ‘compound’ microscopes? Draw a labelled ray diagram showing the image formed by a compound microscope. State the formula used to calculate the magnification produced by a compound microscope. What is the maximum magnification generally possible by using a compound microscope?

OR

(a) Explain how we see different colours of an object.

(b) Why is it that some persons cannot distinguish between different colours?

(c) The chick wakes up with the sunrise and sleeps by the sunset. How does it manage?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q20 :

State Fleming’s left-hand rule. With a labelled diagram, describe the working of an electric motor. What is the function of split ring commutator in a motor?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q21 :

How are inheritary disorders explained?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q22 :

State any harmful effect of lead present as pollutant in air.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q23 :

What are occupational disorders? State briefly how Pneumoconiosis or Byssinosis is caused.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q24 :

State two main objectives of Environmental Laws passed by the Government of India.

Mention names of any two such laws.

OR

List any four practices which help in protecting our environment.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q25 :

List two vital functions of the human kidney. Draw a labelled diagram of an artificial kidney.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q26 :

Draw a diagram showing endocrine glands in a male body. Label the following glands on it:

(i) Pituitary

(ii) Thyroid

(iii) Adrenal

(iv) Testes


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q27 :

Define any three of the following terms used in relation to human reproduction:

(i) Fertilisation

(ii) Implantation

(iii) Placenta

(iv) Gestation

(v) Parturition


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q28 :

Mention briefly the salient points of any one of the following theories of evolution:

(i) Lamarck’s theory

(ii) Darwin’s theory


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q29 :

How is ‘respiration’ different from ‘breathing’? Explain the processes of ‘aerobic’ respiration and ‘anaerobic’ respiration.


Answer :

Please Register/Login to get access to all solutions Facebook Login

10th Science Paper Solutions Set 3 : CBSE Delhi Previous Year 2013 will be available online in PDF book soon. The solutions are absolutely Free. Soon you will be able to download the solutions.