Science and TechnologySEE 2082, Karnali Province
Write very short answers of the following questions. a) Identify a dependent variable in Ohm's law V=IR. b) Write a function of RBC. c) Write any one measure to conserve rare birds in Nepal. d) On…
9Write very short answers of the following questions. a) Identify a dependent variable in Ohm's law V=IR. b) Write a function of RBC. c) Write any one measure to conserve rare birds in Nepal. d) On which principle does Hydraulic brake work? e) If Y is a metal, what is its valency in given product of the chemical equation? f) Write a difference between roasting and calcination. g) Draw a labelled diagram to purify impure copper by electro refining process. h) IVF is a boon for childless couple, why? i) Although shampoo and detergents are better cleaning agents, they degrade our environment. Suggest one natural alternative of such chemical cleansers.
Answer
a) In Ohm's law , the dependent variable is voltage (V). It depends on the values of current (I) and resistance (R).
b) The functions of Red Blood Cells (RBC) are:
- Transport of oxygen from lungs to body cells.
- Transport of carbon dioxide from body cells to lungs.
c) One measure to conserve rare birds in Nepal is:
- Establishing protected areas (e.g., Koshi Tappu Wildlife Reserve) and bird sanctuaries to provide safe habitats.
- Promoting community-based conservation programs to raise awareness and involve locals in bird protection.
d) The Hydraulic brake works on the principle of Pascal’s Law, which states that pressure applied to a confined fluid is transmitted equally in all directions.
e) In the chemical equation:
- The product YN indicates that Y forms a 1:1 ratio with nitrogen (N).
- Since nitrogen has a valency of 3 (as it forms three bonds in compounds like ammonia), but here it forms a single bond with Y, the valency of Y is 3 (to balance the equation and satisfy the octet rule).
f) Difference between Roasting and Calcination:
| Feature | Roasting | Calcination |
|---|---|---|
| Definition | Heating of sulphide ores in the presence of air. | Heating of carbonate or hydroxide ores in the absence of air. |
| Purpose | Converts sulphide ores into oxides. | Converts carbonates/hydroxides into oxides. |
| Example | ||
| Temperature | High temperature (~700–1000°C). | Moderate temperature (~500–900°C). |
| Gas Produced | Sulphur dioxide (SO₂). | Carbon dioxide (CO₂) or water (H₂O). |
g) Labelled Diagram of Electro-Refining of Impure Copper:
Explanation:
- The impure copper acts as the anode, and pure copper is the cathode.
- The electrolyte is a solution of copper sulphate (CuSO₄).
- When an electric current is passed, copper ions (Cu²⁺) move to the cathode and deposit as pure copper.
- Impurities like silver (Ag), gold (Au), and platinum (Pt) settle below the anode as anode mud, while others (e.g., Ni, Zn) remain in the solution.
h) IVF (In Vitro Fertilization) is a boon for childless couples because:
- It helps couples with fertility issues (e.g., blocked fallopian tubes, low sperm count) conceive a child.
- It allows genetic screening to detect hereditary diseases before implantation.
- It provides hope for couples who cannot conceive through natural methods, offering a scientifically assisted reproductive technique.
i) A natural alternative to shampoos and detergents that degrade the environment is:
- Reetha (Soapnut) or Shikakai (natural plant-based cleansers used in Ayurveda).
- These are biodegradable, non-toxic, and gentle on hair and skin while effectively cleaning.
Discussion
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