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10th Students Our Environment

Science Answers Answers to Science Questions **1. Which of the following groups contain only biodegradable items?** (a) Grass, flowers and leather (b) Grass, wood and plastic (c) Fruit-peels, cake and lime-juice (d) Cake, wood and grass Answer: (c) Fruit-peels, cake and lime-juice **2. Which of the following constitute a food-chain?** (a) Grass, wheat and mango (b) Grass, goat and human (c) Goat, cow and elephant (d) Grass, fish and goat Answer: (b) Grass, goat and human **3. Which of the following are environment-friendly practices?** (a) Carrying cloth-bags to put purchases in while shopping (b) Switching off unnecessary lights and fans (c) Walking to school instead of getting your mother to drop you on her scooter (d) All of the above Answer: (d) All of the above **4. What will happen if we kill all the organisms in one trophic level?** Answer: Killing all organisms in one trophic level will disrupt the food cha...
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10th Students Magnetic effects of Electric Current

Science Answers Answers to Science Questions 1. Which of the following correctly describes the magnetic field near a long straight wire? (a) The field consists of straight lines perpendicular to the wire. (b) The field consists of straight lines parallel to the wire. (c) The field consists of radial lines originating from the wire. (d) The field consists of concentric circles centred on the wire. Answer: (d) The field consists of concentric circles centred on the wire. 2. At the time of short circuit, the current in the circuit (a) reduces substantially. (b) does not change. (c) increases heavily. (d) vary continuously. Answer: (c) increases heavily. State whether the following statements are true or false. (a) The field at the centre of a long circular coil carrying current will be parallel straight lines. Answer: True (b) A wire with a green insulation is usually the live wire of an electric supply. Answer: False List ...
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10 Students NCERT Questions Solution Electricity Questions solution

Science Answers Answers to Science Questions 1. A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R’, then the ratio R/R’ is – (d) 25  (c) 5  (b) 1/5  (a) 1/25 Answer: (d) 25 2. Which of the following terms does not represent electrical power in a circuit? (d) V^2/R  (c) VI  (b) IR^2  (a) PR Answer: (b) IR^2 3. An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be – (d) 25 W  (c) 50 W  (b) 75 W  (a) 100 W Answer: (c) 50 W 4. Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be– (d) 4:1  (c) 1:4  (b) 2:1  (a) 1:2 Answer: (c) 1:4 5. How is a voltmeter connected in the circuit to measure t...
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10th Class NCERT Solution The Human Eye and the Colourful World

Science Answers Answers to Science Questions 1. The human eye can focus on objects at different distances by adjusting the focal length of the eye lens. This is due to (a) presbyopia. (b) accommodation. (c) near-sightedness. (d) far-sightedness. Answer: (b) accommodation. 2. The human eye forms the image of an object at its (a) cornea. (b) iris. (c) pupil. (d) retina. Answer: (d) retina. 3. The least distance of distinct vision for a young adult with normal vision is about (a) 25 m. (b) 2.5 cm. (c) 25 cm. (d) 2.5 m. Answer: (c) 25 cm. 4. The change in focal length of an eye lens is caused by the action of the (a) pupil. (b) retina. (c) ciliary muscles. (d) iris. Answer: (c) ciliary muscles. 5. A person needs a lens of power –5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near ...
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10th Light – Reflection and Refraction NCERT Solution

Light – Reflection and Refraction Question 1 1. Which one of the following materials cannot be used to make a lens? (a) Water (b) Glass (c) Plastic (d) Clay Answer 1 Answer: (d) Clay Explanation: A lens is a transparent medium that refracts light. Clay is an opaque material that does not allow light to pass through it, so it cannot be used to make a lens. Question 2 2. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object? (a) Between the principal focus and the centre of curvature (b) At the centre of curvature (c) Beyond the centre of curvature (d) Between the pole of the mirror and its principal focus. Answer 2 Answer: (d) Between the pole of the mirror and its principal focus. Explanation: When an object is placed between the pole and principal focus of a concave mirror, the image formed is virtual, erect, and larger than the object. Question 3 3. Where should an obje...
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10th Students Heredity NCERT Solution given Answers

Genetics Q&A for Class 10 1. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as (a) TTWW (b) TTww (c) TtWW (d) TtWw Answer: (c) TtWW Explanation: Violet (W) is dominant over white (w), and all F 1 plants bear violet flowers, so the tall parent must be homozygous WW. Tall (T) is dominant over short (t), and half the progeny are short, so the tall parent must be heterozygous Tt. 2. A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not? Answer: We cannot conclude whether light-coloured eyes are dominant or recessive solely from this observati...
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10th How do organisms Reproduce NCERT Solution

Reproduction Q&A 1. Asexual reproduction takes place through budding in (a) Amoeba. (b) Yeast. (c) Plasmodium. (d) Leishmania. Answer: (b) Yeast Step-by-step reasoning: Budding is a type of asexual reproduction where a new organism grows out of the body of the parent. In yeast, a small protuberance (bud) forms on the parent cell, its nucleus divides, and one nucleus migrates into the bud. The bud enlarges and eventually detaches as an independent yeast cell. Other organisms listed reproduce by binary fission (Amoeba), sporozoite formation (Plasmodium), or other modes (Leishmania). 2. Which of the following is not a part of the female reproductive system in human beings? (a) Ovary (b) Uterus (c) Vas deferens (d) Fallopian tube Answer: (c) Vas deferens Step-by-step reasoning: Ovary, uterus, and fallopian tube are intrinsic to the female reproductive tract. Vas defe...
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