Sakil Ahmed Classes

  Note: Use this Question Bank to write comfortably . 1. Choose the correct answer: (i) Which one of the following is a non-renewable resource? Answer: (d) Natural gas (ii) Which one of the following is abiotic resource? Answer: (a) Air (iii) Which one of the following resources is a non-renewable resource? Answer: (c) Iron (iv) Which one of the following is man-made resource? Answer: (b) Irrigation (v) Which one of the following is an abiotic resource? Answer: (i) Air (vi) Which of the following is not a primary occupation? Answer: (c) manufacturing process (vii) Which of the following is not applied to 'resource'? Answer: (a) cannot be exchanged (viii) Which one of the following is non-renewable resource? Answer: (b) Mineral oil (ix) Which one of the following is not included in tertiary occupation? Answer: (c) Mineral resource collection (x) Choose the correct set of statements about the IUCN: Correct Answer: (a) (i),  (iii) (i) IUCN was formed in the year 1948. ✔ (ii) The ...

  A. Answer in Detail  1. With the help of an experiment, explain the neutralization reaction. Answer:   Objective : To demonstrate the reaction between an acid and a base to form salt and water.   Materials : Hydrochloric acid (HCl), sodium hydroxide (NaOH), phenolphthalein indicator, beaker, dropper, glass rod, evaporating dish.   Procedure :   1.  First we pour 10 mL of NaOH into a beaker.   2. Add 2-3 drops of phenolphthalein. The solution turns pink (basic).   3. Slowly add HCl while stirring. The pink color fades as neutralization occurs.   4. Stop when the solution becomes colorless (pH 7).   5. Evaporate the solution to obtain NaCl crystals.   Conclusion : Acid + Base → Salt + Water.    2. How to identify NaOH and HCl using turmeric powder? Answer: Turmeric acts as a natural indicator:    Yellow in acidic/neutral solutions.    Red ...

  A. Answer in Detail: 1. **Question:** How is temperature measured with a thermometer?      **Answer:** Temperature is measured using a thermometer containing a thermometric fluid (e.g., mercury or alcohol) in a sealed glass tube. The fluid expands or contracts with temperature changes, and its level is read against a calibrated scale (Celsius, Fahrenheit, or Kelvin).   2. **Question:** Distinguish between clinical and laboratory thermometers.      **Answer:**      - Clinical Thermometer : Measures human body temperature (35°C–42°C), has a kink to retain readings.      - Laboratory Thermometer : Measures a broader range (-10°C–110°C), no kink, requires manual resetting.   3. **Question:** List the precautions that should be taken while taking temperature.      **Answer:**The precautions are- Cleaning the thermometer, avoid touching the bulb, waiting for stabiliza...

 **A. Answer in Detail** 1. Differentiate between plant and animal fibres.  Ans: Plant fibres are derived from plants, while animal fibres are obtained from animals.   - Sources :     - Plant fibres : Cotton (from cotton plant), jute (from jute plant), flax (linen).     - Animal fibres: Wool (from sheep, goats), silk (from silkworms).   - Composition :     - Plant fibres are primarily made of cellulose.     - Animal fibres consist of proteins (e.g., keratin in wool, fibroin in silk).   - Properties :     - Plant fibres are breathable and absorbent but less durable.     - Animal fibres are elastic, insulating, and stronger.   2. How is wool obtained from sheep?  Ans: Wool is obtained from sheep by the following process- - Shearing : The thick coat of hair (fleece) is shaved off using electric clippers.   - Scouring : The fleece is was...

Note : Use this Question Bank to write comfortably. A. MCQs . **(i) Emulsification of fat molecule is carried out by-**   **Answer:** (c) Bile salts   *(Bile salts emulsify fats, increasing the surface area for enzyme action.)*   **(ii) Anaerobic respiration occurs in-**   **Answer:** (d) Cytoplasm   *(Anaerobic respiration (glycolysis) occurs in the cytoplasm, while aerobic respiration happens in mitochondria.)*   **(iii) The enzyme which converts starch to simple sugar is-**   **Answer:** (a) amylase   *(Amylase breaks down starch into maltose and other simple sugars.)*   **(iv) The process fulfilling carbon and energy requirements of autotrophic organisms is-**   **Answer:** (a) Photosynthesis   *(Photosynthesis converts CO₂ and light into glucose and energy.)*   **(v) The part of the brain responsible for hunger and thirst is-**   **Answer:** (d) hypothal...