CBSE Class 10 Science 2014 Question Paper

Name the two components of peripheral nervous system.

A charge of $150\text{ C}$ flows through a wire in one minute. Find the electric current flowing through it.

What are hot spots inside earth's crust?

Explain why, an aqueous solution of sodium sulphate is neutral while an aqueous solution of sodium carbonate is basic in nature.

When hydrogen gas is passed over heated copper (II) oxide, copper and steam are formed. Write the balanced chemical equation for this reaction and state (i) the substance oxidized and (ii) the substance reduced in the reaction.

Why do herbivores have longer, small intestine than carnivores?

State reason for the following: (i) Lemon is used for restoring the shine of tarnished copper vessels. (ii) A metal sulphide is converted into its oxide to extract the metal from the sulphide ore. (iii) Copper wires are used in electrical connections.

Select (i) combination reaction, (ii) decomposition reaction and (iii) displacement reaction from the following chemical equations: (i) $\text{ZnCO}_3\text{(s)} \rightarrow \text{ZnO(s)} + \text{CO}_2\text{(g)}$ (ii) $\text{Pb(s)} + \text{CuCl}_2\text{(aq)} \rightarrow \text{PbCl}_2\text{(aq)} + \text{Cu(s)}$ (iii) $\text{NaBr(aq)} + \text{AgNO}_3\text{(aq)} \rightarrow \text{AgBr(s)} + \text{NaNO}_3\text{(aq)}$ (iv) $\text{H}_2\text{(g)} + \text{Cl}_2\text{(g)} \rightarrow 2\text{HCl(g)}$ (v) $\text{Fe}_2\text{O}_3 + 2\text{Al} \rightarrow \text{Al}_2\text{O}_3 + 2\text{Fe}$ (vi) $3\text{H}_2\text{(g)} + \text{N}_2\text{(g)} \rightarrow 2\text{NH}_3\text{(g)}$ (vii) $\text{CaCO}_3\text{(s)} \xrightarrow{\text{Heat}} \text{CaO(s)} + \text{CO}_2\text{(g)}$

State reason for the following: (i) Dry $\text{HCl}$ gas does not change the colour of the dry blue litmus paper. (ii) Alcohol and glucose also contain hydrogen, but do not conduct electricity. (iii) Concentration of $\text{H}_3\text{O}^+$ ion is affected when a solution of an acid is diluted.

State the kind of chemical reactions in the following examples: (i) Digestion of food in stomach (ii) Combustion of coal in air (iii) Heating of limestone

The rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms. Give reason. State the pathway of air from nostrils to the lungs in human beings.

Mention three characteristic features of hormonal secretions in human beings.

(a) State the purpose of formation of urine. (b) What will happen if there is no tubular reabsorption in the nephrons of kidney?

A circuit has a line of $5\text{ A}$. How many lamps of rating $40\text{ W}$; $220\text{ V}$ can simultaneously run on this line safely?

The resistance of a wire of $0.01\text{ cm}$ radius is $10\ \Omega$. If the resistivity of the material of the wire is $50 \times 10^{-8}\ \Omega\cdot\text{m}$, find the length of the wire.

Show four different ways in which four resistors of $r\ \Omega$ each may be connected in a circuit. In which case is the equivalent resistance of the combination: (i) maximum; (ii) minimum?

Amit lives in Delhi and is much concerned about the increasing electricity bill of his house. He took some steps to save electricity and succeeded in doing so. (i) Mention any two steps that Amit might have taken to save electricity. (ii) Amit fulfilled his duty towards the environment by saving electricity. How? (iii) Which alternative source of energy would you suggest Amit to use?

List any three qualities of an ideal source of energy.

(a) Define corrosion. (b) What is corrosion of iron called? (c) How will you recognise the corrosion of silver? (d) Why corrosion of iron is a serious problem? (e) How can we prevent corrosion?

Write balanced chemical equations for the following statements: (i) $\text{NaOH}$ solution is heated with zinc granules. (ii) Excess of carbon dioxide gas is passed through lime water. (iii) Dilute sulphuric acid reacts with sodium carbonate. (iv) Egg shells are dropped in hydrochloric acid. (v) Copper (II) oxide reacts with dilute hydrochloric acid.

(a) Write three main functions of the nervous system. (b) In the absence of muscle cells, how do plant cells show movement?

(a) Draw magnetic field lines of a bar magnet. "Two magnetic field lines never intersect each other." Why? (b) An electric oven of $1.5\text{ kW}$ is operated in a domestic circuit ($220\text{ V}$) that has a current rating of $5\text{ A}$. What result do you expect in this case? Explain.

What is meant by resistance of a conductor? Name and define its SI unit. List the factors on which the resistance of a conductor depends. How is the resistance of a wire affected if: (i) its length is doubled, (ii) its radius is doubled?

(i) Establish a relationship to determine the equivalent resistance $R$ of a combination of three resistors having resistances $R_1$, $R_2$ and $R_3$ connected in parallel. (ii) Three resistors are connected in an electrical circuit. Calculate the resistance between A and B.

Four students studied reactions of zinc and sodium carbonate with dilute hydrochloric acid and dilute sodium hydroxide solutions and presented their results as follows. The (✓) shows evolution of gas and (-) shows no reaction. The right set is:

Dilute $\text{NaOH}$ solution and solid sodium carbonate:

The colour of $\text{Cu}$ metal is:

Shashank was asked to carry out a displacement reaction which would show the following: (i) Formation of colourless solution (ii) Black deposits The reactants he should use are:

Mrignayani was doing the experiment of comparing reactivity of metals in the laboratory. She was given aluminium metal and was told to check reactivity by using four solutions (A, B, C, and D, where A is aluminium sulphate). She would observe that reaction takes place in:

In an experiment to find the equivalent resistance of a series combination of two resistances of $3\ \Omega$ and $4\ \Omega$ in the circuit diagram given. The circuit will give:

A student joined three resistances (two of $30\ \Omega$ in series, connected in parallel with a $20\ \Omega$ resistor) to a $7.5\text{ V}$ source. The current recorded by the ammeter (A) is:

The iodine solution is:

Choose the correct set-up to demonstrate that $\text{CO}_2$ is given out during respiration:

An iron nail is dipped in the solution of copper sulphate for about 30 minutes, state the change in colour observed. Give the reason for the change.

A student while verifying Ohm's law calculated the value of resistance of the resistor for each set of observation. However, the values of resistance were slightly different from the actual value. Is his experiment wrong? Justify your answer.

Draw a labelled diagram of stomatal apparatus with closed stomatal pore.