WBCHSE Class 11 Physics Transmission Of Heat Very Short Answer Questions

Transmission Of Heat Very Short Answer Type Questions

Question 1. Name the quickest mode of transmission of heat.
Answer: Radiation

Question 2. Name the mode of transmission of heat in which the molecules of the material medium do not change their positions.
Answer: Conduction

Question 3. Name the mode of transmission of heat in which heat is transferred by actual displacement of the material molecules.
Answer: Convection

Question 4. Name the mode of transmission of heat in which the material molecules has no role.
Answer: Radiation

Question 5. In which mode of transmission, the medium is not heated at the time of heat transmission?
Answer: Radiation

Question 6. Name the mode, in which heat is always transmitted in straight paths.
Answer: Radiation

Question 7. Which metal has the highest thermal conductivity?
Answer: Silver

Question 8. Name a liquid which is a good conductor of heat,
Answer: Mercury

Question 9. Thermal conductivity of copper is 0,92 CCS unit, Express it in SI unit.
Answer: 386.4 J · m^-1 · K^-1 · s^-1

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Question 10. On what factor does the coefficient of thermal conductivity of a conductor depend?
Answer: On the material

WBBSE Class 11 Transmission of Heat Very Short Answer Questions

Question 11. What is the value of k of an ideal conductor?
Answer: Infinfie

Question 12. State whether the gradient of temperature In case of conduction of heat is positive or negative.
Answer: Negative

Question 13. Of copper, iron, wood, and mercury which one has the highest thermal resistivity?
Answer: Wood

Question 14. Two metallic rods having equal lengths and equal cross-sectional areas are coated with wax uniformly. Now one end of each rod is kept at the same high temperature, The lengths of the rods up to which wax melts are 2 cm and 3cm respectively. What is the ratio of the coefficients of thermal conductivity of the rods?
Answer: 4:9

Question 15. On which properties of the material of a conductor does the heat conduction depend till the temperature of the conducting rod increases?
Answer: Coefficient of thermal conductivity, specific heat, and density

Question 16. On which properties of the material of a conductor does the heat conduction depend when the conducting rod is in a steady state?
Answer: Coefficient of thermal conductivity

Question 17. What do you mean by thermal steady state in heat conduction?
Answer: A constant temperature is attained by each point on the die conductor

Question 18. A combined strip is produced by riveting two plates. In case of heat conduction through it which property remains die same for die two plates?
Answer: The rate of heat conduction

Question 19. Almost all metals are bad conductors of heat. Is the statement true or false?
Answer: False

Question 20. What is the CGS unit of the coefficient of thermal conductivity? Answer: cal • cm^-1 • °C^-1 • s^-1

Question 21. What is die dimension of the coefficient of thermal conductivity? Answer: MLT^-3Θ^-1

Question 22. How does the rate of heel conduction change if the temperature difference between the two ends of a conducting rod be made twice the previous value?
Answer: Doubled

Question 23. If a conducting rod is covered by an insulating material then in a steady state the rate of beat conduction will ———
Answer: Remain unchanged]

Question 24. The ratio of both the lengths and diameters of two cylindrical rods is 1:2. What will be the ratio of their thermal resistances?
Answer: 2: 1

Real-Life Examples of Heat Transmission

Question 25. If the coefficient of thermal conductivity of the material of a conductor is k, density is ρ and specific heat is s, then what will be the thermal diffusivity of the material?
Answer: \(\left[\frac{k}{\rho s}\right]\)

Question 26. The coefficient of thermal conductivity of a rod is 4 unit. What will be its thermal resistivity?
Answer: 0.25 unit

Question 27. One end of a rod covered with an insulating material is kept at 100°C and the other end is kept at the room temperature of 30°C. What will be the temperature of the mid-point of the rod in steady state?
Answer: 65°C

Question 28. Two metallic rods of equal lengths but having coefficients of thermal conductivity k₁ and k₂ and areas of cross-section A₁ and A₂ respectively are taken. The temperatures of their ends are equal. If the rate of heat conduction in them is equal \(k_1 / k_2\) = _____
Answer: \(A_1 / A_2\)

Question 29. Two metallic strips of equal cross sections are riveted together to form a combined strip. If the thermal resistances of the individual strips are R₁ and R₂, then what will be the thermal resistance of the combined strip?
Answer: R₁ + R₂

Question 30. If the velocity of light in vacuum is c then what will be the velocity of radiant heat in it?
Answer: c

Question 31. The upper layer of the atmosphere remains cold compared to the earth’s surface during the daytime. What does it indicate?
Answer: Radiant heat does not heat the medium

Question 32. What type of wave is the radiant heat?
Answer: Electromagnetic wave

Question 33. Which part of electromagnetic radiation is the most active for thermal radiation?
Answer: Infrared

Question 34. In which way does visible light differ from radiant heat?
Answer: Wavelength

Question 35. Name the body which absorbs the whole part of incident radiation. Answer: Ideal black body

Question 36. What is the absorptive power of an ideal black body?
Answer: 1

Question 37. At what temperature does a body not radiate heat?
Answer: 0K

Step-by-Step Explanations for Very Short Heat Transfer Questions

Question 38. Newton’s law of cooling is the consequence of which law?
Answer: Stefan’s law

Question 39. How many times will the rate of heat absorbed by the earth be if the temperature of the sun is doubled?
Answer: 16 times

Question 40. If a sphere and a cube made of the same material and of equal masses be kept at 200°C in air then which one of them will cool faster?
Answer: The cube

Question 41. Through solid, heat cannot be transmitted by convection. Is the statement true or false?
Answer: True

Question 42. What is the approximate range of wavelengths of thermal radiation? Answer: 6000 Å to 10^-4 m

Question 43. The frequency of radiant heat is of the order of 1014 Hz. Is the statement true or false?
Answer: True

Question 44. From Kirchhoff’s law it is known that a good radiator is also a bad absorber. Is the statement true or false?
Answer: False

Question 45. Which type of body reflects all the incident radiant heat?
Answer: Ideal white body

Question 46. A star A looks reddish from the earth, while another star B looks white. What conclusion can be drawn from this observation?
Answer: The temperature of A is less

Question 47. What is the condition for which Newton’s law of cooling is applicable?
Answer: Low-temperature difference

Question 48. For which type of surface of a hot body the rate of heat radiation will be rapid?
Answer: Black and rough

Question 49. If an iron ball and an iron plate of the same mass are heated to the same temperature, then which of them will cool faster?
Answer: Plate

Question 50. An iron plate takes times t₁, t₂, and t₃ to cool down from 100°C to 90°C, 90°C to 80°C and 80°C to 70°C respectively. What will be the relation between t₁, t₂, and t₃?
Answer: t₁<t₂ <t₃

Thermal Conductivity and Its Importance Short Answers

Question 51. The temperature of a black body is increased from 7°C to 2870 C. How does the rate of its heat radiation change?
Answer: 16 times

Question 52. Which mode of transmission of heat depends on the force of gravity?
Answer: Connection

Question 53. Due to this mode of transmission of heat land breeze and sea breeze are formed in coastal regions.
Answer: Connection

Question 54. Name one greenhouse gas.
Answer: Carbon dioxide (CO₂)