MAHESH TUTORIALS. (ii) At the time of short circuit, the current in the circuit... (a) increases (b) decreases (c) remains (d) increases in steps

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1 S.S.C. MAHESH TUTORIALS Paper - Test - III Batch : SB Marks : 30 Date : SCIENCE Chapter : 3, 4, 5, 8, 1, 13 Time : 1 hr. 15 min. SECTION - A Q.I (A) Rewrite the following statements by choosing the correct 1 option : (i) 1 cal =... joule. (a) 10 7 (b) 10 5 (c) 41.8 (d) 4.18 (ii) At the time of short circuit, the current in the circuit.... (a) increases (b) decreases (c) remains (d) increases in steps Q.I (B) Rewrite the Column II so as to match the Column I : 1 Column I Column II (i) A.C. current (a) One directional current (ii) D.C. current (b) Behaves like a magnet (c) Transmission over long distance Q.I (C) State whether the following statements are True or False : 1 (i) Magnetic field increase as we go away from a magnet. (ii) Carbon dioxide is a non-metallic oxide. Q.II Answer the following as required : (Any Two) 4 (i) Explain the working of electric fuse. (ii) State Fleming s left hand rule. (iii) Sodium bicarbonate is used in fire extinguishers. Why? (iv) Name a few natural indicators. Q.III (A) Solve the following : (Any One) (i) 40 J heat is generated in a conductor of resistance 50, when 0.A current is passed across it. Find for how long current will pass through it. (ii) A washing machine rated 300 W operates one hour/ day. If the cost of unit is Rs. 3.00, find the cost of the energy to operate a washing machine for the month of March. Q.III (B) Draw neat and labelled diagram : (Any One) (i) Magnetic lines of force around a bar magnet. (ii) Magnetic lines of force through a solenoid.

2 Paper - Q.IV Answer the following : (Any One) (i) Explain the working of electric motor. (ii) State the uses of bleaching powder. Q.V Write balanced equations : (Any One) (i) Bleaching powder is exposed to air. (ii) Iron reacts with dilute hydrochloric acid. (iii) Copper oxide reacts with dilute hydrochloric acid. SECTION - B Q.I Fill in the blanks : (i) Metals react with dilute acids to give... and... gas is liberated. (ii) Aluminum undergoes an oxidation reaction forming a thin layer of.... (iii) Dominant character masks the... character. (iv) Yeast reproduces by.... Q.II (A) Give scientific reasons : (Any One) (i) Ionic compounds are formed due to the combination of metals and non-metals. (ii) Multicellular organisms show complex ways of reproduction. (iii) Phenotypic and genotypic ratios are different. Q.II (B) Answer the following : (Any Two) 4 (i) Explain the properties of ionic compounds. (ii) Define Roasting. (iii) Write balanced equations : Iron reacts with dilute sulphuric acid. (iv) What is mitosis? Represent in diagramatically. (v) How do genes regulate the height of a plant? Q.III Draw a neat and labelled diagram of the following : (Any One) (i) Binary fission in amoeba. (ii) Longitudinal section of flower. (iii) Human male reproductive system. Q.IV Answer the following : (Any One) 5 (i) Describe sexual reproduction in plants. (Diagram not required) (ii) With the help of a diagram (Punnett square) show a Mendelian experiment where tall pea plant bearing red flowers is crossed with a short pea plant bearing white flowers. Write both the phenotypic and genotypic ratio for F generation. Best Of Luck

3 Paper - S.S.C. MAHESH TUTORIALS Test - III Batch : SB Marks : 30 SCIENCE Chapter : 3, 4, 5, 8, 1, 13 Date : MODEL ANSWER PAPER Time : 1 hr. 15 min. SECTION - A A.I (A) Rewrite the following statements by choosing the correct option : (i) 1 cal = 4.18 joule. (ii) At the time of short circuit, the current in the circuit increases. A.I (B) Rewrite the Column II so as to match the Column I : Column I Column II (i) A.C. current Transmission over long distance (ii) D.C. current One directional current A.I (C) State whether the following statements are True or False : (i) False. Magnetic field decreases as we go away from a magnet. (ii) True. A.II Answer the following as required : (Any Two) (i) 1. An electric fuse protects circuits and appliances by stopping the flow of any excess electric current.. The fuse is placed in series with the device. It consist of a piece of wire made of an alloy of low melting point for example lead and tin. 3. If a current larger than the specified value flows through the circuit, the temperature of the fuse wire increases. 4. This melts the fuse wire and breaks the circuit. 5. The fuses used for domestic purpose are stated as 1A, A, 3A, 5A, 10A etc. (ii) Stretch the forefinger, the central finger and the thumb of you left hand mutually perpendicular to each other. If the forefinger shows the direction of the field and the central finger shows the direction of the current, then the thumb will point towards the direction of the motion of the conductor. (iii) 1. The fire extinguisher contains a solution of sodium bicarbonate in water and sulphuric acid in a separate container inside it.. When the fire extinguisher is operated by pressing the knob on it, the sulphuric acid gets mixed with sodium bicarbonate solution producing a lot of carbon dioxide gas.

4 Paper - (iv) NaHCO + H SO 4 Na SO 4 + H O + CO 3. Carbon dioxide gas is neither combustible nor helps combustion. It is heavier than air and cuts off the supply of oxygen from air and hence extinguishes the fire. 4. Hence, sodium bicarbonate is used in fire extinguishers. Turmeric (blue dye), litmus (purple dye), red cabbage extract (red dye), rose-petals, beetroot are natural indicators. A.III (A) Solve the following : (Any One) (i) Given : Heat (H) = 40 J Resistance (R) = 50 Current (I) = 0. A To find : Time (t) Formula : H = I Rt Solution : H = I Rt 40 = (0.) 50 t 40 = t t = t = t = 10 sec t = min. Time for which current is passed through the conductor is min. (ii) Given : Power (P) = 300 W = Time (t) = 31 hrs. Unit cost = Rs. 3 To find : Cost of energy Formula : Electric power = = 0.3 kw Energy consumed Time in hours Solution : Electric power = Energy consumed Time in hours Energy consumed = Electric power time in hours = = 9.3 kwh

5 Paper - Cost of energy = = Rs. 7.9 The cost of the energy to operate a washing machine for the month of March is Rs A.III (B) Draw neat and labelled diagram : (Any One) (i) Magnetic lines of force around a bar magnet. N S Magnetic lines of force around a bar magnet (ii) Magnetic lines of force through a solenoid. S N + K Magnetic lines of force through a solenoid

6 Paper - A.IV Answer the following : (Any One) (i) Working of the electric motor : (a) When current is passed through the coil ABCD, arms AB and CD experience force. (b) According to Fleming s left hand rule the force experienced by arm AB is in the upward direction and arm CD in the downward direction. Both these forces are equal and opposite. (c) This force rotates the coil in clockwise direction until the coil is vertical. At this position, the contact between commutator and brushes break. So the supply to the coil is cut off. Thus no force acts on the coil. (d) But the coil does not stop due to inertia. It goes on rotating until the commutator again comes in contact with the brushes B 1 and B. Again the current starts passing through the coil and the arm AB rotates through 90º, 180º, 70º and 360 degrees. (e) Now the force acting on arm AB is upward and CD is downward. Again this force moves the coil in clockwise direction. (f) Thus, the coil rotates with the help of electrical energy. The coil of DC motor continues to rotate in the same direction. (ii) 1. It is used to disinfect water.. It is used for bleaching cotton and linen in textile industry and bleaching wood pulp in paper industry. It is also used for bleaching washed clothes in laundary, the bleaching action is due to chlorine released by it. 3. It is used as an oxidizing agent in many chemical industries. 4. It is used to prepare organic solvent chloroform which is also used as an anaesthetic. A.V (i) (ii) (iii) Write balanced equations : (Any One) When bleaching powder is exposed to air, CO from air decomposes the powder slowly to produce chlorine. CaOCl (s) + CO (g) CaCO 3(s) + Cl (g) Bleaching Carbon Calcium Chlorine powder dioxide carbonate When iron reacts with cold dilute hydrochloric acid to give iron(ii) chloride and hydrogen gas. Fe (s) + HCl (aq) FeCl (aq) + H (g) Iron Hydrochloric acid Iron chloride Hydrogen When copper chloride reacts with dilute hydrochloric acid to give a blue solution of copper chloride. CuO (s) + HCl (aq) CuCl (aq) + H O (l) Copper oxide Hydrochloric acid Copper chloride Water

7 Paper - SECTION - B A.I Fill in the blanks : (i) Metals react with dilute acids to give salt and hydrogen gas is liberated. (ii) Aluminum undergoes an oxidation reaction forming a thin layer of aluminium oxide. (iii) Dominant character masks the recessive character. (iv) Yeast reproduces by budding. A.II (A) Give scientific reasons : (Any One) (i) 1. A metallic atom loses electrons and gets converted into a positively charged ion (cation).. A non-metallic atom gains electrons and gets converted into a negatively charged ion(anion). 3. These cations and anions have opposite charge and experience a strong attraction for each other, so they remain tightly held together forming ionic or electrovalent bond. Hence ionic compounds are formed due to the combination of metals and non-metals. Eg. : NaCl. Na + Cl Na + + Cl NaCl, 8, 1, 8, 7, 8, 8, 8 (ii) 1. Multicellular organisms have different cell types which perform different functions.. They have special organs, placed at a definite place in the body which are formed by specific tissues. 3. In such organised organisms, method of cell-by-cell division to reproduce is impractical. 4. Therefore, multicellular organisms show complex ways of reproduction. (iii) 1. Phenotype is the appearance of any detectable characteristic feature of an individual whereas the genotype is the genetic composition of an individual.. The genes responsible for any particular character is present in pairs. 3. Though, there are two genes, the phenotype depends on the presence of the dominant gene. Eg. the genotype for red colour flower is Rr or RR. 4. Therefore, phenotypic and genotypic ratios are different. A.II (B) Answer the following : (Any Two) (i) 1. Ionic compounds are solids and hard due to strong force of attraction between positive and negative ions.

8 Paper - (ii) (iii). They are generally brittle and break into pieces when pressure is applied. 3. Ionic compounds have high melting and boiling points, as a considerable amount of energy is required to break the strong intermolecular attraction. 4. They are generally soluble in water and insoluble in solvents such as kerosene, petrol etc. 5. Ionic compounds in the solid state do not conduct electricity because the movement of ions in the solid state is not possible due to their rigid structure, but they conduct electricity in the molten state. The conduction of electricity through a solution involves the movements of charged (ions) particles. A solution of an ionic compound in water contains ions, which move to the opposite electrodes when electricity is passed through the solution. The process of converting sulphide ore into oxide by heating strongly in presence of excess air is called roasting. When iron reacts with dilute sulphuric acid to give iron sulphate and hydrogen gas. Fe (s) + H SO 4(aq) FeSO 4(aq) + H (g) Iron Sulphuric acid Iron sulphate Hydrogen (iv) 1. Mitosis is a type of cell division leading to growth and development.. It occurs in somatic cells. 3. Diagramatically it can be represented as : Parent cell n Two daughter cells n (restoring original n chromosomal number) (v) 1. In plants, growth hormones are present.. The height gained by plants depends upon the amount of growth hormone produced by the plant. 3. The quantity of hormones produced by the plants depends upon the efficiency of the concerned enzyme. 4. Efficient enzymes produce hormones in greater quantity resulting in the plants gaining height and thus becoming tall. 5. On the other hand, if the enzymes are less efficient, they produce less quantity of growth hormone which results in the stunted growth of the plants. 6. The production of enzymes is controlled by genes. Therefore, genes regulate the height of a plant.

9 Paper - A.III (i) Draw a neat and labelled diagram of the following : (Any One) Binary fission in amoeba. Parent cell Nucleus dividing Cytoplasm dividing Two daughter cells (ii) Longitudinal section of flower. Stigma Carpel Style Petal Ovary Anther Filament Sepal Stamen (iii) Human male reproductive system. Bladder Seminal vesicle Prostate gland Vas deferens Urethra Epididymis Testis Penis

10 Paper - A.IV (i) Answer the following : (Any One) The process of sexual reproduction in plants involves three processes : 1. Pollination. Fertilization 3. Germination. 1. Pollination : (a) The process of transfer of pollen grains from the anther to the stigma is called pollination. (b) If this transfer of pollen occurs in the same flower or another flower of the same plant, it is known as self pollination. (c) On the other hand, if pollen is transferred from one flower to the flower of another plant of the same species, it is known as cross pollination. The agents of cross pollination are wind, water or animals.. Fertilization : (a) After the pollen grain lands on the stigma, it germinates. (b) The pollen tube grows out from a pollen grain. It travels through the style to reach the ovary. (c) Each pollen tube contains two male gametes and releases them near the egg. (d) One male gamete fuses with the egg cell to form zygote. (e) The second male gamete fuses with the secondary nucleus in the embryo sac to form endosperm. This is called as double fertilization. (f) The zygote develops into embryo and the endosperm serves as nutritive tissue for the growing embryo. This embryo is capable of growing into a new plant. 3. Germination : (a) After fertilization, the zygote divides several times to form an embryo within the ovule. (b) The ovule develops into a seed and ovary develops into the fruit. (c) The seed contains the future plant. It develops into the seedling under appropriate conditions. This process is known as germination. 5 (ii) 1. Tallness is the dominant character and shortness is a recessive character of pea plant.. Similarly red colour of the flower is the dominant character and the white colour of the flower is the recessive character. 3. Therefore, the gene combinations for the characters will be TT (tallness), tt (shortness), RR (red flowers), rr (white flowers). 5

11 Paper - P 1 generation TTRR ttrr Gametes TR TR tr tr F 1 generation gametes Mendel s dihybrid cross (formation of gametes) TtRr TtRr TtRr TtRr Cross between TtRr and TtRr : TR Tr tr tr TR TTRR TTRr TtRR TtRr Tr TTRr TTrr TtRr Ttrr tr TtRR TtRr ttrr ttrr tr TtRr Ttrr ttrr ttrr The phenotype and genotype is shown in the table below : Phenotype No. of squares in chequer board Genotype No. of squares in chequer board Tall with red flowers Short with red flowers Tall with white flowers Short with white flowers TTRR TTRr TtRR TtRr Ttrr ttrr ttrr Ttrr The phenotypic ratio of F generation is 9 : 3 : 3 : 1 and the genotypic ratio is 1 : : : 4 : 1 : 1 : : : 1. ttrr