9TH/PHY/8/ MCQs

 Here's a set of 45 multiple-choice questions (MCQs) categorized into easy, moderate, and tough questions, along with the correct answers provided at the end in a three-column format.


 Easy Questions (15)


1. What happens to gases when they are heated?  

   a) They contract  

   b) They expand  

   c) They remain the same  

   d) They freeze  


2. What is the relationship between temperature and heat?  

   a) They are the same  

   b) Temperature is a measure of heat  

   c) Heat is a measure of temperature  

   d) Neither is related  


3. Which unit is commonly used to measure temperature?  

   a) Joule  

   b) Kelvin  

   c) Newton  

   d) Pascal  


4. What is the boiling point of water at standard atmospheric pressure?  

   a) 0°C  

   b) 100°C  

   c) 212°F  

   d) Both b and c  


5. What scale is used to measure absolute temperature?  

   a) Celsius  

   b) Fahrenheit  

   c) Kelvin  

   d) Rankine  


6. What is the specific heat capacity of water?  

   a) 1 J/g°C  

   b) 4.18 J/g°C  

   c) 2 J/g°C  

   d) 3.6 J/g°C  


7. Which of the following describes latent heat of fusion?  

   a) Heat required to boil a liquid  

   b) Heat required to melt a solid  

   c) Heat required to heat a liquid  

   d) None of the above  


8. What happens to the temperature of a substance during a phase change?  

   a) It increases  

   b) It decreases  

   c) It remains constant  

   d) It fluctuates  


9. What is the formula for converting Celsius to Fahrenheit?  

   a) F = C + 32  

   b) F = (C × 9/5) + 32  

   c) F = C × 5/9  

   d) F = (C + 32) × 9/5  


10. In which state of matter do particles have the least kinetic energy?  

   a) Solid  

   b) Liquid  

   c) Gas  

   d) Plasma  


11. What is the effect of wind on evaporation?  

   a) Decreases the rate  

   b) Increases the rate  

   c) No effect  

   d) Stops evaporation  


12. What is thermal expansion?  

   a) The increase in mass of a substance when heated  

   b) The increase in volume of a substance when heated  

   c) The increase in temperature of a substance when heated  

   d) None of the above  


13. Which of the following is an example of thermal expansion?  

   a) Heating a balloon  

   b) Ice melting  

   c) Water freezing  

   d) All of the above  


14. What is the principle behind a liquid-in-glass thermometer?  

   a) Changes in pressure  

   b) Changes in volume  

   c) Changes in color  

   d) Changes in density  


15. What is the primary function of a bimetallic strip?  

   a) To measure pressure  

   b) To measure temperature  

   c) To regulate temperature  

   d) To expand  


 Moderate Questions (15)


16. Explain the difference between temperature and heat.  

   a) Temperature measures thermal energy, heat is energy transfer  

   b) Heat is a measure of thermal energy, temperature is energy transfer  

   c) Both are the same  

   d) Neither relates to energy  


17. What are the fixed points in a thermometer?  

   a) 0°C and 100°C  

   b) 0°F and 100°F  

   c) 32°F and 212°F  

   d) 273.15K and 373.15K  


18. How is temperature converted from Celsius to Fahrenheit?  

   a) F = (C × 1.8) + 32  

   b) F = (C × 2) + 32  

   c) F = (C × 1.8) - 32  

   d) F = C + 32  


19. What is meant by the specific heat capacity of a substance?  

   a) The amount of heat needed to change the temperature of 1 kg by 1°C  

   b) The heat required to change the state of a substance  

   c) The total heat in a substance  

   d) None of the above  


20. How does the surface area of a liquid affect its rate of evaporation?  

   a) No effect  

   b) Increases evaporation rate  

   c) Decreases evaporation rate  

   d) Evaporation stops  


21. Describe the importance of water’s high specific heat capacity.  

   a) It helps in temperature regulation  

   b) It prevents rapid temperature changes  

   c) It supports marine life  

   d) All of the above  


22. What happens to the temperature of a substance during the latent heat of fusion?  

   a) It increases  

   b) It remains constant  

   c) It decreases  

   d) It fluctuates  


23. Explain why different liquids have different rates of evaporation.  

   a) Due to different molecular weights  

   b) Due to intermolecular forces  

   c) Due to temperature  

   d) All of the above  


24. How does atmospheric pressure affect the boiling point of a liquid?  

   a) Increases with pressure  

   b) Decreases with pressure  

   c) No effect  

   d) Fluctuates  


25. What is thermal expansion in solids?  

   a) Increase in length due to temperature increase  

   b) Decrease in length due to temperature increase  

   c) No change in length  

   d) Expansion only at certain points  


26. What is the effect of temperature on the density of liquids?  

   a) Increases with temperature  

   b) Decreases with temperature  

   c) Remains constant  

   d) Fluctuates  


27. How does the specific heat capacity of a substance affect its heating?  

   a) Higher specific heat requires more energy  

   b) Lower specific heat requires more energy  

   c) Specific heat has no effect  

   d) None of the above  


28. Explain why the temperature of a liquid remains constant during boiling.  

   a) Energy goes into breaking intermolecular bonds  

   b) Energy increases temperature  

   c) No energy is added  

   d) None of the above  


29. How is temperature measured using a thermocouple?  

   a) By measuring resistance  

   b) By measuring voltage  

   c) By measuring mass  

   d) None of the above  


30. Why is the Kelvin scale considered absolute?  

   a) It starts from absolute zero  

   b) It has no negative values  

   c) It is used in scientific calculations  

   d) All of the above  


Tough Questions (15)


31. Derive the formula for converting Kelvin to Celsius.  

   a) K = C + 273.15  

   b) K = C - 273.15  

   c) K = C × 273.15  

   d) K = C ÷ 273.15  


32. How does a bimetal strip work using the concept of thermal expansion?  

   a) Different materials expand at different rates  

   b) Both materials expand equally  

   c) It doesn't expand  

   d) None of the above  


33. Discuss the significance of specific heat capacity in designing heating systems.  

   a) It affects the efficiency of energy use  

   b) It determines heating time  

   c) It ensures even heating  

   d) All of the above  


34. How does thermal expansion explain the formation of cracks in heated materials?  

   a) Expansion causes stress in materials  

   b) Materials do not crack  

   c) It only applies to liquids  

   d) None of the above  


35. Explain why metals expand at different rates when heated.  

   a) Due to atomic structure differences  

   b) All metals expand the same  

   c) Due to molecular weight  

   d) None of the above  


36. How is latent heat used in the process of distillation?  

   a) To vaporize liquid  

   b) To cool liquids  

   c) To change liquid state  

   d) All of the above  


37. Discuss the effect of thermal expansion on the structural stability of buildings.  

   a) Expansion can cause structural damage  

   b) No effect on structures  

   c) Only affects the outer walls  

   d) None of the above  


38. How does thermal expansion relate to the molecular motion of particles?  

   a) Increased temperature causes increased motion  

   b) Decreased temperature causes increased motion  

   c) No relationship  

   d) None of the above  


39. Why do different materials have different specific heat capacities?  

   a) Due to molecular structure  

   b) Due to mass  

   c) All materials have the same specific heat  

   d) None of the above  


40. How is the concept of latent heat used in refrigeration systems?  

   a) To absorb heat from surroundings  

   b) To cool the system  

   c) To maintain temperature  

   d) All of the above  


41. How does the nature of a liquid affect its rate of evaporation?  

   a) Different intermolecular forces  

   b) Same for all liquids  

   c) Only temperature matters  

   d) None of the above  


42. What is the effect of


 pressure on the boiling point of a liquid in a closed container?  

   a) It increases  

   b) It decreases  

   c) No effect  

   d) Fluctuates  


43. Explain why the boiling point of water decreases at higher altitudes.  

   a) Lower atmospheric pressure  

   b) Higher temperature  

   c) Increased humidity  

   d) None of the above  


44. How does thermal conductivity affect the rate of heat transfer?  

   a) Higher conductivity increases rate  

   b) Lower conductivity increases rate  

   c) No effect on heat transfer  

   d) None of the above  


45. Discuss the practical applications of specific heat capacity in everyday life.  

   a) Cooking  

   b) Heating systems  

   c) Climate control  

   d) All of the above  


Answer Key


| Question | Answer |

|----------|--------|

| 1        | b      |

| 2        | b      |

| 3        | b      |

| 4        | d      |

| 5        | c      |

| 6        | b      |

| 7        | b      |

| 8        | c      |

| 9        | b      |

| 10       | a      |

| 11       | b      |

| 12       | b      |

| 13       | a      |

| 14       | b      |

| 15       | a      |

| 16       | a      |

| 17       | a      |

| 18       | a      |

| 19       | a      |

| 20       | b      |

| 21       | d      |

| 22       | b      |

| 23       | d      |

| 24       | a      |

| 25       | a      |

| 26       | b      |

| 27       | a      |

| 28       | a      |

| 29       | b      |

| 30       | d      |

| 31       | a      |

| 32       | a      |

| 33       | d      |

| 34       | a      |

| 35       | a      |

| 36       | a      |

| 37       | a      |

| 38       | a      |

| 39       | a      |

| 40       | d      |

| 41       | a      |

| 42       | a      |

| 43       | a      |

| 44       | a      |

| 45       | d      |


Feel free to adjust or add more questions based on your needs!