Home
Class 12
PHYSICS
Raed the following passage and and answe...

Raed the following passage and and answer the following questions.
Stefan's law states that the ernergy emitted per second per unit area of the perfect black body is directly proportional to fourth power of its absolute temperature i.e. `EpropT^(4)` or `E=sigmaT^(4)` where `sigma` is called Stefan's constant. If the body is placed in enclosure maintained at temperature `T_(0)` then `E=sigma(T^(4)-T_(0)^(4))`. If temperature difference between the body and the surroundings is very small then energy emitted per second per unit area of the body and surrounding i.e `Eprop(T-T_(0))`. This is known as Newton's Law of cooling and is a special case of Stefan's Law.
Two bodies P and Q are having equal surface areas and are maintained at temperature `17^(@)C` and `27^(@)C` respectively. Then radiant energy emitted per second are in the ratio of :

A

`16:81`

B

`8:27`

C

`2:3`

D

`7:8`

Text Solution

Verified by Experts

The correct Answer is:
D

`(E_(1))/(E_(2))+(sigmaT_(1)^(4))/(sigmaT_(2)^(4))=((290)/(300))^(4)= 87=7/8`
So correct choice is (d).
Promotional Banner

Topper's Solved these Questions

  • TRANSFERENCE OF HEAT

    MODERN PUBLICATION|Exercise Multiple Choice Questions (Level - III) Questions From AIEEE/JEE Examination)|5 Videos
  • TRANSFERENCE OF HEAT

    MODERN PUBLICATION|Exercise Recent Competitive Questions|4 Videos
  • TRANSFERENCE OF HEAT

    MODERN PUBLICATION|Exercise Recent Competitive Questions|4 Videos
  • SOLIDS & SEMICONDUCTOR DEVICES

    MODERN PUBLICATION|Exercise Revision Test|28 Videos
  • UNIFORM CIRCULAR MOTION

    MODERN PUBLICATION|Exercise Revision Test |57 Videos

Similar Questions

Explore conceptually related problems

Define criticial temperature (T_(e))

If K _(1) and K_(2) are the rate constants at temperatures T _(1) and T_(2) respectively and E _(a) is the activatino energy, then :

Two spherical black bodies of radii r_(1) and r_(2) and with surface temperatures T_(1) and T_(2) respectively, radiate the same power. Then r_(1)//r_(2) must be equal to

Animals having a built-in thermostat to maintain constant body temperature are known as

MODERN PUBLICATION-TRANSFERENCE OF HEAT -Multiple Choice Questions (Level - II)
  1. Statement - I : A hallow metallic closed containes maintained at a uni...

    Text Solution

    |

  2. Statement - I : The absorbtance of a perfact black body is unity. S...

    Text Solution

    |

  3. Raed the following passage and and answer the following questions. S...

    Text Solution

    |

  4. A body cools from 50^(@)C to 40^(@)C in 5 minutes and from 40^(@)C to ...

    Text Solution

    |

  5. Time taken by the body to cool from 45^(@)C to 35^(@)C is

    Text Solution

    |

  6. The plots of intensity versus wavelength for three black bodies at tem...

    Text Solution

    |

  7. Two spheres of the same material have radii 1 m and 4 m and temperatur...

    Text Solution

    |

  8. The graph shown in the adjacent diagram, represents the variation of t...

    Text Solution

    |

  9. Three discs A, B and C having radii 2m, 4 m and 6 m respectively are c...

    Text Solution

    |

  10. Two identical conducting rods are first connected independently to two...

    Text Solution

    |

  11. A radiation of energy E falls normally on a perfectly reflecting surfa...

    Text Solution

    |

  12. A body with area A at maintained temperature T and emissivity e=0.6 is...

    Text Solution

    |

  13. Ice starts forming in a lake water at 0^(@)C when the atmospheric temp...

    Text Solution

    |

  14. A body is placed in an insulating container at temperature 227^(@)C. I...

    Text Solution

    |

  15. A cylindrical rod is having temperature T(1) and T(2) at its ends. The...

    Text Solution

    |

  16. The rate of cooling at 600 K, if surrounding tempearture is 300 K is R...

    Text Solution

    |

  17. One end of a copper rod of length 1.0m and area of cross-section 10^(-...

    Text Solution

    |

  18. Consider a compound slab consisting of two different materials having ...

    Text Solution

    |

  19. The dimensions of thermal resistance are :

    Text Solution

    |

  20. There is formation of layer of snow x cm thick on water, when the temp...

    Text Solution

    |