Author: Vidhyarthi Darpan

BIOLOGY 

SCIENCE Paper – 3 

SECTION I 

Q.1 (a) Name the following: 

     (i) The organization which procures and supplies blood during an emergency. 

     (ii) The blood vessel which supplies blood to the liver. 

     (iii) The number of chromosomes present in a nerve cell of a human being.

     (iv) The layer of the eyeball that forms the transparent Cornea. 

     (v) The wax-like layer on the epidermis of leaves which reduces transpiration.

(b) Choose the correct answer from each of the four options given below: 

      (i) The number of Spinal nerves in a human being are: 

           A. 31 pairs 

           B. 10 pairs 

           C. 21 pairs 

           D. 30 pairs 

(ii) Which one of the following is non-biodegradable? 

        A. DDT 

        B. Vegetable peel 

        C. Cardboard 

        D. Bark of trees 

(iii) Aqueous humour is present between the: 

        A. Lens and Retina 

        B. Iris and Lens 

        C. Cornea and Iris  

       D. Cornea and Lens 

(iv) A strong chemical substance which is used on objects and surfaces in our  

       surroundings to kill germs: 

       A. Cresol 

       B. Carbolic acid 

       C. Iodine 

       D. Mercurochrome 

(v) Which one of the following is a Greenhouse gas? 

       A. Oxygen 

       B. Methane 

       C. Sulphur dioxide 

       D. Nitrogen 

(c) Complete the following paragraph by filling in the blanks (i) to (v) with appropriate words: 

To test a leaf for starch, the leaf is boiled in water to (i)__________. It is then  boiled in Methylated spirit to (ii)__________. The leaf is dipped in warm water to soften it. It is placed in a petri dish, and (iii)__________ solution is added. The region of the leaf which contains starch, turns (iv)__________ and the region which does not contain starch, turns (v)__________. 

(d) Match the items given in Column A with the most appropriate ones in Column B and rewrite the correct matching pairs          

Column A	Column B
(i) Cretinism	(a) Hypersecretion of adrenal cortex
(ii) Diabetes insipidus	(b) Hyposecretion of Thyroxine
(iii) Exophthalmic       Goitre	© Hyposecretion of growth hormone
(iv) Adrenal virilism	(d) Hyposecretion of Vasopressin
(v) Dwarfism	(e) Hyposecretion of adrenal cortex
	(f) Hypersecretion of Growth hormone
	(g) Hypersecretion of Thyroxine

(e) Correct the following statements by changing the underlined words: 

     (i) Normal pale yellow colour of the urine is due to the presence of the pigment Melanin. 

    (ii) The outermost layer of Meninges is Pia mater. 

   (iii)The cell sap of root hair is Hypotonic. 

   (iv) Xylem transports starch from the leaves to all parts of the plant body. 

   (v) Nitrogen bonds are present between the complementary nitrogenous bases  of 

(f) Choose between the two options to answer the Q.specified in the brackets for the following:  

An example is illustrated below. 

Example: Corolla or Calyx (Which is the outer whorl?)    Answer: Calyx 

   (i) Blood in the renal artery or renal vein (Which one has more urea?) 

  (ii) Perilymph or endolymph (Which one surrounds the organ of Corti?) 

  (iii) Lenticels or stomata (Which one remains open always?) 

  (iv) Sclerotic layer or choroid layer (Which one forms the Iris?) 

  (v) Blood in the pulmonary artery or pulmonary vein (Which one contains less oxyhaemoglobin?) 

(g) Given below is a representation of a type of pollution.  

     Study the picture and answer the questions: 

    (i) Name the type of pollution shown in the picture. 

    (ii) Name one source of this pollution. 

   (iii) How does this pollution affect human health? 

   (iv) Write one measure to reduce this pollution. 

   (v) State one gaseous compound that leads to the depletion of the ozone layer and creates ‘Ozone holes’. 

(h) Choose the ODD one out from the following terms given and name the CATEGORY to which the others belong:  

Example: Nose, Tongue, Arm, Eye 

Answer: Odd Term – Arm, Category – Sense organs 

      (i) Detergents, X-rays, sewage, oil spills 

     (ii) Lumen, muscular tissue, connective tissue, pericardium 

    (iii) Dendrites, Medullary Sheath, Axon, Spinal cord 

    (iv) Centrosome, Cell wall, Cell membrane, Large vacuoles 

   (v) Prostate gland, Cowper’s gland, seminal vesicle, seminiferous tubules. 

SECTION II 

Q.2 (a) The diagram given below represents a stage during cell division.  

Study the same and answer the questions that follow: 

       (i) Identify whether it is a plant cell or an animal cell.  

            Give a reason in support of your answer. 

      (ii) Name the stage depicted in the diagram.  

           What is the unique feature observed in this stage? 

     (iii) Name the type of cell division that occurs during:  

           1. Replacement of old leaves by new ones. 

           2. Formation of gametes. 

    (iv) What is the stage that comes before the stage shown in the diagram? 

    (v) Draw a neat, labelled diagram of the stage mentioned in (iv) above keeping the chromosome number constant. 

(b) Mention the exact location of the following:  

      (i) Epididymis 

     (ii) Lacrimal gland 

     (iii) Malleus 

     (iv) Hydathodes 

     (v) Pulmonary semilunar valve 

 

Q.3 (a) Given below are diagrams showing the different stages in the process of 

      fertilisation of an egg in the human female reproductive tract.  

      Study the diagrams and answer the questions: 

       A                    B                    C                        D

      (i) Arrange the letters given below each diagram in a logical sequence to show the correct order in the process of fertilisation. 

     (ii) Where does fertilisation normally take place? What is ‘Implantation’ that follows fertilisation? 

   (iii) Mention the chromosome number of the egg and zygote in humans. 

   (iv) Explain the term ‘Gestation’. How long does Gestation last in humans? 

   (v) Draw a neat, labelled diagram of a mature human sperm. 

(b) A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours  and then placed in bright sunlight for a few hours. Observe the diagrams and  answer the questions. 

      (i) What aspect of photosynthesis is being tested in the above diagram? 

     (ii) Represent the process of photosynthesis in the form of a balanced equation.  

     (iii) Why was the plant kept in the dark before beginning the experiment? 

     (iv) What will be the result of the starch test performed on leaf ‘A’ shown in the diagram? Give an example of a plant with variegated leaves. 

     (v) Draw a neat labelled diagram of a chloroplast. 

 

Q.4 (a) The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions: 

       (i) Name the phenomenon that is depicted in the diagram. Define the phenomenon. 

      (ii) Give the technical term for the point of contact between the two nerve cells. 

     (iii) Name the parts numbered 1, 2 and 3. 

     (iv) How does the arrangement of neurons in the spinal cord differ from that of  the brain? 

     (v) Mention two ways by which the spinal cord is protected in our body. 

(b) Give appropriate biological or technical terms for the following:  

      (i) Process of maintaining water and salt balance in the blood. 

      (ii) Hormones which regulate the secretion of other endocrine glands. 

      (iii) Movement of molecules of a substance from their higher concentration to lower concentration when they are in direct contact. 

      (iv) The condition in which a pair of chromosomes carry similar alleles of a particular character. 

     (v) The complex consisting of a DNA strand and a core of histones. 

     (vi) The onset of menstruation in a young girl. 

     (vii)Squeezing out of white blood cells from the capillaries into the surrounding tissues. 

   (viii) The fluid which surrounds the foetus. 

    (ix) The relaxation phase of the heart. 

    (x) The difference between the birth rate and the death rate. 

 

Q.5 (a) The diagram given below is that of a structure present in a human kidney.  

      Study the same and answer the questions that follow: 

     (i) Name the structure represented in the diagram. 

     (ii) What is the liquid entering part ‘1’ called?  

          Name two substances present in this liquid that are reabsorbed in the tubule. 

    (iii) What is the fluid that comes to part ‘2’ called?  

           Name the main nitrogenous waste in it. 

   (iv) Mention the three main steps involved in the formation of the fluid mentioned in (iii) above.  

   (v) Name the substance which may be present in the fluid in part ‘2’ if a person suffers from Diabetes mellitus. 

(b) Differentiate between the following pairs on the basis of what is indicated in the  brackets.  

     (i) Leaf and Liver [form in which glucose is stored] 

    (ii) ATP and AIDS [expand the abbreviations] 

   (iii) Testosterone and Oestrogen [organ which secretes] 

   (iv) Ureter and Urethra [function] 

   (v) Hypotonic solution and Hypertonic solution [condition of a plant cell when placed in them] 

 

Q.6 (a) Given below is a diagram of a human blood smear.  

     Study the diagram and answer the questions that follow: 

     (i) Name the components numbered ‘1’ to ‘4’. 

    (ii) Mention two structural differences between the parts ‘1’ and ‘2’. 

    (iii) Name the soluble protein found in part ‘4’ which forms insoluble threads during clotting of blood. 

    (iv) What is the average lifespan of the component numbered ‘1’? 

    (v) Component numbered ‘1’ do not have certain organelles but are very efficient in their function. Explain. 

(b) Give biological explanations for the following: 

      (i) Education is very important for population control. 

      (ii) The placenta is an important structure for the development of a foetus. 

      (iii) All the food chains begin with green plants. 

      (iv) Plants growing in fertilized soil are often found to wilt if the soil is not adequately watered. 

     (v) We should not put sharp objects into our ears. 

 

Q.7 (a) The diagram below represents a process in plants.  

    The setup was placed in bright sunlight. Answer the following questions: 

  (i) Name the physiological process depicted in the diagram.  

       Why was oil added to the water? 

  (ii) When placed in bright sunlight for four hours, what do you observe with   

        regard to the initial and final weight of the plant?  

        Give a suitable reason for your answer. 

  (iii) What happens to the level of water when this setup is placed in: 

          1. Humid conditions? 

          2. Windy conditions? 

  (iv) Mention any three adaptations found in plants to overcome the process mentioned in (i). 

   (v) Explain the term ‘Guttation’. 

(b) A pea plant which is homozygous for Green pods which are inflated [GGII] is crossed with a homozygous plant for yellow pods which are constricted [ggii].  

     Answer the following questions:  

    (i) Give the phenotype and genotype of the F1 generation. Which type of pollination has occurred to produce F1 generation? 

   (ii) Write the phenotypic ratio of the F2 generation. 

   (iii) Write the possible combinations of the gametes that can be obtained if two F1 hybrid plants are crossed. 

  (iv) State Mendel’s law of ‘Segregation of Gametes’. 

  (v) What is the scientific name of the plant which Mendel used for his experiments on inheritance? 

CHEMISTRY 

SCIENCE Paper – 2 

SECTION I 

Q.1 (a) Choose the correct answer from the options given below: 

  (i) The salt solution which does not react with ammonium hydroxide is: 

      A. Calcium Nitrate  

      B. Zinc Nitrate  

      C. Lead Nitrate  

      D. Copper Nitrate 

 (ii) The organic compound which undergoes substitution reaction is: 

      A. C2H2 

      B. C2H4 

      C. C10H18 

      D. C2H6 

 (iii) The electrolysis of acidified water is an example of: 

     A. Reduction 

     B. Oxidation 

     C. Redox reaction 

     D. Synthesis 

 (iv) The IUPAC name of dimethyl ether is: 

    A. Ethoxy methane 

    B. Methoxy methane 

    C. Methoxy ethane 

    D. Ethoxy ethane 

(v) The catalyst used in the Contact Process is: 

     A. Copper  

     B. Iron  

     C. Vanadium pentoxide  

     D. Manganese dioxide 

(b) Give one word or a phrase for the following statements: 

      (i) The energy released when an electron is added to a neutral gaseous  isolated atom to form a negatively charged ion. 

      (ii) Process of formation of ions from molecules which are not in ionic state.  

     (iii) The tendency of an element to form chains of identical atoms. 

  (iv) The property by which certain hydrated salts, when left exposed to atmosphere, lose their water of crystallization and crumble into powder.  

      (v) The process by which sulphide ore is concentrated. 

(c) Write a balanced chemical equation for each of the following: 

      (i) Action of concentrated sulphuric acid on carbon. 

     (ii) Reaction of sodium hydroxide solution with iron (III) chloride solution. 

     (iii) Action of heat on aluminum hydroxide. 

     (iv) Reaction of zinc with potassium hydroxide solution. 

     (v) Action of dilute hydrochloric acid on magnesium sulphite. 

(d) (i) Give the IUPAC name for each of the following: 

      (ii) Write the structural formula of the two isomers of butane.  

(e) State one relevant observation for each of the following: 

     (i) Lead nitrate solution is treated with sodium hydroxide solution drop wise till it is in excess. 

    (ii) At the anode, when molten lead bromide is electrolyzed using graphite electrodes. 

    (iii) Lead nitrate solution is mixed with dilute hydrochloric acid and heated. 

    (iv) Anhydrous calcium chloride is exposed to air for some time. 

    (v) Barium chloride solution is slowly added to sodium sulphate solution. 

(f) Give a reason for each of the following: 

    (i) Ionic compounds have a high melting point. 

    (ii) Inert gases do not form ions. 

    (iii) Ionisation potential increases across a period, from left to right. 

    (iv) Alkali metals are good reducing agents. 

    (v) Conductivity of dilute hydrochloric acid is greater than that of acetic acid. 

(g) Name the gas that is produced in each of the following cases: 

     (i) Sulphur is oxidized by concentrated nitric acid. 

    (ii) Action of dilute hydrochloric acid on sodium sulphide. 

    (iii) Action of cold and dilute nitric acid on copper. 

    (iv) At the anode during the electrolysis of acidified water. 

    (v) Reaction of ethanol and sodium. 

(h) Fill up the blanks with the correct choice given in brackets. 

   (i) Ionic or electrovalent compounds do not conduct electricity in their_____________ state. (fused / solid) 

  (ii) Electrolysis of aqueous sodium chloride solution will form _______at the cathode. (hydrogen gas / sodium metal) 

  (iii) Dry hydrogen chloride gas can be collected by ___________displacement of air. (downward / upward) 

   (iv) The most common ore of iron is _____________. (calamine / haematite) 

    (v) The salt prepared by the method of direct combination is _____________. (iron (II) chloride / iron (III) chloride) 

SECTION II 

Q.2 (a) (i) What do you understand by a lone pair of electrons? 

      (ii) Draw the electron dot diagram of Hydronium ion. (H=1; O=8) 

(b) In Period 3 of the Periodic Table, element B is placed to the left of element A. On the basis of this information, choose the correct word from the brackets to complete the following statements: 

   (i) The element B would have (lower / higher) metallic character than A. 

   (ii) The element A would probably have (lesser / higher) electron affinity than B. 

  (iii) The element A would have (greater / smaller) atomic size than B. 

(c) Copy and complete the following table which refers to the conversion of ions to neutral particles.  

Conversion	Ionic Equation	Oxidation /  Reduction
Chloride ion to chlorine  molecule Lead (II) ion to lead	(i) __________  (iii)_________	(ii)__________  (iv)_________

 

Q.3 (a) (i) Write the balanced chemical equation to prepare ammonia gas in the laboratory by using an alkali. 

      (ii) State why concentrated sulphuric acid is not used for drying ammonia gas. 

      (iii) Why is ammonia gas not collected over water? 

(b) (i) Name the acid used for the preparation of hydrogen chloride gas in the laboratory. Why is this particular acid preferred to other acids? 

     (ii) Write the balanced chemical equation for the laboratory preparation of hydrogen chloride gas. 

(c) For the preparation of hydrochloric acid in the laboratory: 

     (i) Why is direct absorption of hydrogen chloride gas in water not feasible? 

     (ii) What arrangement is done to dissolve hydrogen chloride gas in water? 

(d) For the electro-refining of copper: 

    (i) What is the cathode made up of? 

   (ii) Write the reaction that takes place at the anode. 

 

Q.4 (a) The percentage composition of a gas is: Nitrogen 82.35%, Hydrogen 17.64%.  

      Find the empirical formula of the gas. [N = 14, H = 1] 

(b) Aluminum carbide reacts with water according to the following equation: 

                          Al4C3 + 12H2O –> 4Al (OH)3 + 3CH4 

  (i) What mass of aluminum hydroxide is formed from 12g of aluminum carbide? 

  (ii) What volume of methane at s.t.p. is obtained from 12g of aluminum carbide? 

          [Relative molecular weight of Al4C3 = 144; Al(OH)3 = 78] 

(c) (i) If 150 cc of gas A contains X molecules, how many molecules of gas B will be present in 75 cc of B?  

       The gases A and B are under the same conditions of temperature and  pressure. 

       (ii) Name the law on which the above problem is based.  

(d) Name the main component of the following alloys: 

      (i) Brass 

     (ii) Duralumin 

 

Q.5 (a) Complete the following table which relates to the homologous series of hydrocarbons. 

General  formula	IUPAC name of the  homologous series	Characteristic bond  type	IUPAC name of the  first member of the  series
CnH2n – 2	(A) __________	(B)__________	(C)__________
CnH2n + 2	(D)__________	(E)__________	(F)__________

(b) (i) Name the most common ore of the metal aluminum from which the metal is extracted. Write the chemical formula of the ore. 

     (ii) Name the process by which impure ore of aluminum gets purified by  using concentrated solution of an alkali. 

    (iii) Write the equation for the formation of aluminum at the cathode during  the electrolysis of alumina. 

 

Q.6 (a) A compound X (having vinegar like smell) when treated with ethanol in the  presence of the acid Z, gives a compound Y which has a fruity smell.  

      The reaction is:  

     (i) Identify Y and Z. 

     (ii) Write the structural formula of X. 

     (iii) Name the above reaction. 

(b) Ethane burns in oxygen to form CO2 and H2O according to the equation: 

                      2C2H6 + 7O2 –> 4CO2 + 6H2O.  

      If 1250 cc of oxygen is burnt with 300 cc of ethane. 

      Calculate: 

       (i) the volume of CO2 formed. 

       (ii) the volume of unused O2. 

(c) Three solutions P, Q and R have pH value of 3.5, 5.2 and 12.2 respectively. 

      Which one of these is a: 

     (i) Weak acid? 

    (ii) Strong alkali? 

 

Q.7 (a) Give a chemical test to distinguish between the following pairs of chemicals: 

     (i) Lead nitrate solution and Zinc nitrate solution 

     (ii) Sodium chloride solution and Sodium nitrate solution 

(b) Write a balanced equation for the preparation of each of the following salts: 

     (i) Copper sulfate from Copper carbonate. 

    (ii) Zinc carbonate from Zinc sulfate. 

(c) (i) What is the type of salt formed when the reactants are heated at a suitable temperature for the preparation of Nitric acid? 

     (ii) State why for the preparation of Nitric acid, the complete apparatus is made  up of glass. 

(d) Which property of sulfuric acid is shown by the reaction of concentrated sulfuric acid with:  

       (i) Ethanol? 

       (ii) Carbon? 

PHYSICS 

SCIENCE Paper – 1 

SECTION I 

Q.1 (a) (i) State and define the S.I. unit of power.  

              (ii) How is the unit horse power related to the S.I. unit of power? 

(b) State the energy changes in the following cases while in use:  

     (i) An electric iron. 

    (ii) A ceiling fan. 

(c) The diagram below shows a lever in use:  

  (i) To which class of levers does it belong? 

  (ii) Without changing the dimensions of the lever, if the load is shifted towards  the fulcrum what happens to the mechanical advantage of the lever?  

(d) (i) Why is the ratio of the velocities of light of wavelengths 4000Å and in vacuum 1:1? 

      (ii) Which of the above wavelengths has a higher frequency?  

(e) (i) Why is the motion of a body moving with a constant speed around a circular path said to be accelerated? 

      (ii) Name the unit of physical quantity obtained by the formula  Where K: kinetic energy, V: Linear velocity. 

 

Q.2 (a) The power of a lens is –5D. 

     (i) Find its focal length. 

     (ii) Name the type of lens. 

(b) State the position of the object in front of a converging lens if: 

     (i) It produces a real and same size image of the object. 

    (ii) It is used as a magnifying lens. 

(c) (i) State the relation between the critical angle and the absolute refractive index of a medium. 

     (ii) Which colour of light has a higher critical angle? Red light or Green light. 

(d) (i) Define scattering.  

      (ii) The smoke from a fire looks white.  

           Which of the following statements is true? 

           1. Molecules of the smoke are bigger than the wavelength of light.  

           2. Molecules of the smoke are smaller than the wavelength of light.  

(e) The following diagram shows a 60^o, 30^o, 90^oglass prism of critical angle  42^o. Copy the diagram and complete the path of incident ray AB emerging out of the  prism marking the angle of incidence on each surface. 

 

Q.3 (a) Displacement distance graph of two sound waves A and B, travelling in a

     medium, are as shown in the diagram below.  

Study the two sound waves and compare their:  

   (i) Amplitudes  

  (ii) Wavelengths 

(b) You have three resistors of values 2Ω, 3Ω and 5Ω. How will you join them so that the total resistance is more than 7Ω?  

    (i) Draw a diagram for the arrangement. 

   (ii) Calculate the equivalent resistance. 

(c) (i) What do you understand by the term nuclear fusion? 

    (ii) Nuclear power plants use nuclear fission reaction to produce electricity. What is the advantage of producing electricity by fusion reaction? 

(d) (i) What do you understand by free vibrations of a body?  

      (ii) Why does the amplitude of a vibrating body continuously decrease during  damped vibrations? 

(e) (i) How is the e.m.f. across primary and secondary coils of a transformer related with the number of turns of coil in them?  

     (ii) On which type of current do transformers work? 

 

Q.4 (a) (i) How can a temperature in degree Celsius be converted into S.I. unit of temperature?  

     (ii) A liquid X has the maximum specific heat capacity and is used as a coolant in Car radiators. Name the liquid X. 

(b) A solid metal weighing 150 g melts at its melting point of 800 ^oC by providing heat at the rate of 100 W. The time taken for it to completely melt at the same  temperature is 4 min. What is the specific latent heat of fusion  of the metal? 

(c) Identify the following wires used in a household circuit:  

     (i) The wire is also called as the phase wire. 

     (ii) The wire is connected to the top terminal of a three pin socket. 

(d) (i) What are isobars?  

     (ii) Give one example of isobars. 

(e) State any two advantages of electromagnets over permanent magnets.

 

SECTION II 

Q.5 (a) (i) Derive a relationship between S.I. and C.G.S. unit of work.  

     (ii) A force acts on a body and displaces it by a distance S in a direction at an  angle θ with the direction of force. What should be the value of θ to get the maximum positive work? 

(b) A half metre rod is pivoted at the centre with two weights of 20 gf and 12 gf suspended at a perpendicular distance of 6 cm and 10 cm from the pivot respectively as shown below. 

(i) Which of the two forces acting on the rigid rod causes clockwise moment?

(ii) Is the rod in equilibrium? 

(iii) The direction of 20 gf force is reversed. What is the magnitude of the resultant moment of the forces on the rod? 

(c) (i) Draw a diagram to show a block and tackle pulley system having a velocity  ratio of 3 marking the direction of load(L), effort(E) and tension(T).  

(ii) The pulley system drawn lifts a load of 150 N when an effort of 60 N is applied. Find its mechanical advantage.  

(iii) Is the above pulley system an ideal machine or not? 

 

Q.6 (a) A ray of light XY passes through a right angled isosceles prism as shown below. 

(i) What is the angle through which the incident ray deviates and emerges out of the prism?  

(ii) Name the instrument where this action of prism is put into use. 

(iii) Which prism surface will behave as a mirror? 

(b) An object AB is placed between O and F1 on the principal axis of a

     converging lens as shown in the diagram. 

       Copy the diagram and by using three standard rays starting from point A, obtain  an image of the object AB.  

(c) An object is placed at a distance of 12 cm from a convex lens of focal length  8 cm. Find:  

    (i) the position of the image  

   (ii) nature of the image 

 

Q.7 (a) Draw the diagram of a right angled isosceles prism which is used to make an inverted image erect. 

(b) 

The diagram above shows a wire stretched over a sonometer. Stems of two  vibrating tuning forks A and B are touched to the wooden box of the sonometer. It is observed that the paper rider (a small piece of paper folded at the centre)  present on the wire flies off when the stem of vibrating tuning fork B is touched  to the wooden box but the paper just vibrates when the stem of vibrating tuning  fork A is touched to the wooden box.  

    (i) Name the phenomenon when the paper rider just vibrates.  

    (ii) Name the phenomenon when the paper rider flies off.  

    (iii) Why does the paper rider fly off when the stem of tuning fork B is touched  to the box? 

(c) A person is standing at the sea shore. An observer on the ship which is anchored in between a vertical cliff and the person on the shore, fires a gun. The person  on the shore hears two sounds, 2 seconds and 3 seconds after seeing the smoke  of the fired gun. If the speed of sound in the air is 320 ms^-1then calculate: 

    (i) the distance between the observer on the ship and the person on the shore.  

    (ii) the distance between the cliff and the observer on the ship. 

 

Q.8 (a) (i) A fuse is rated 8A. Can it be used with an electrical appliance rated 5 KW, 200 V? Give a reason.  

     (ii) Name two safety devices which are connected to the live wire of a household electric circuit. 

(b) (i) Find the equivalent resistance between A and B. 

     (ii) State whether the resistivity of a wire changes with the change in the thickness of the wire. 

(c) An electric iron is rated 220V, 2kW.  

     (i) If the iron is used for 2h daily find the cost of running it for one week if it  costs ` 4.25 per kWh.  

    (ii) Why is the fuse absolutely necessary in a power circuit? 

 

Q.9  (a) (i) Heat supplied to a solid changes it into liquid. What is this change in phase  called?  

     (ii) During the phase change does the average kinetic energy of the molecules  of the substance increase?  

    (iii) What is the energy absorbed during the phase change called? 

(b) (i) State two differences between “Heat Capacity” and “Specific Heat Capacity”.  

     (ii) Give a mathematical relation between Heat Capacity and Specific Heat Capacity.  

(c) The temperature of 170g of water at 50°C is lowered to 5°C by adding certain amount of ice to it. Find the mass of ice added.  

    Given: Specific heat capacity of water = 4200 J kg^-1 ⁰C^-1and Specific latent  heat of ice = 336000 J kg^-1 

 

Q.10 (a) 

The diagram shows a coil wound around a U shape soft iron bar AB.

(i) What is the polarity induced at the ends A and B when the switch is pressed? 

(ii) Suggest one way to strengthen the magnetic field in the electromagnet. 

(iii) What will be the polarities at A & B if the direction of current is reversed in the circuit? 

(b) The ore of Uranium found in nature contains 92U²³⁸ and 92U²³⁵. Although both  the isotopes are fissionable, it is found out experimentally that one of the two  isotopes is more easily fissionable. 

      (i) Name the isotope of Uranium which is easily fissionable. 

      (ii) Give a reason for your answer. 

      (iii) Write a nuclear reaction when Uranium 238 emits an alpha particle to form  a Thorium (Th) nucleus.  

(c) Radiations given out from a source when subjected to an electric field in a direction perpendicular to their path are shown below in the diagram. The arrows show the path of the radiation A, B and C. Answer the followingquestions in terms of A, B and C. 

(i) Name the radiation B which is unaffected by the electrostatic field. 

(ii) Why does the radiation C deflect more than A? 

(iii) Which among the three causes the least biological damage externally?  

(iv) Name the radiation which is used in carbon dating.