Home
Class 11
PHYSICS
The total radiant energy per unit area, ...

The total radiant energy per unit area, normal to the direction of incidence, received at a distance `R` from the centre of a star of radius `r` whose outer surface radiates as a black body at a temperature `T K` is given by
(where `sigma` is Stefan's constant)

A

`(sigmar^(2)T^(4))/(R^(2))`

B

`(sigmar^(2)T^(4))/(4pir^(2))`

C

`(sigmar^(4)T^(4))/(r^(4))`

D

`(4pisigmar^(2)T^(4))/(R^(2))`

Text Solution

Verified by Experts

Promotional Banner

Topper's Solved these Questions

  • SYSTEM OF PARTICLES AND ROTATIONAL MOTION

    DISHA|Exercise PHYSICS|45 Videos

  • THERMODYNAMICS

    DISHA|Exercise PHYSICS|44 Videos

Similar Questions

Explore conceptually related problems

The gravitational potential energy of a body at a distance r from the centre of the Earth is U where r gt R (radius of Earth). What is the weight of body at the point ?

The sun having surface temperature Ts radiates like a black body. The rasius of sun is Rs and earth is at a distance R from the surface of sun. Earth absorbs radiations falling on its surface from sun only and is at constant temperature T. If radiations falling on earth's surface are alomost parallel and earth also radiates like a blackbody, then

A body with surface area (A), temperature (T) and emissivity (e) = 0.6 is kept inside a spherical black body. What will be the maximum energy radiated ? [ sigma is Stefan's constant]

A highly conducting solid sphere of radius R density rho and specific heat s is kept in an evacuted chamber. A parallel beam of thermal radiation of instensity I is incident on its surfcae Consider the sphere to be a perfectly black body and its temperature at certain instant considered at t =0 is T_(0) [Take Stefan's constant as sigma ] Answer the following questions based on above information The equation which gives the temperature T of the sphere as a function of time is .

A highly conducting solid sphere of radius R density rho and specific heat s is kept in an evacuted chamber. A parallel beam of thermal radiation of instensity I is incident on its surfcae Consider the sphere to be a perfectly black body and its temperature at certain instant considered at t =0 is T_(0) [Take Stefan's constant as sigma ] Answer the following questions based on above information The maximum attainable temperature of the sphere is .

Assuming the sun to have a spherical outer surface of radius r radiating like a black body at temperature t^(@)C . The power received by a unit surface (normal to the incident rays) at a distance R from the centre of the sun is where sigma is the Stefan's constant.

Knowledge Check

  • The magnitude of an electric intensity at a point which is at a distance 'r' from the centre of a charged spherical conductor of radius 'R' in terms of the surface charge density 'sigma' is given by 'E' where

    A
    `E=(sigma)/(Kepsi_(0)r^(2))`
    B
    `E=(sigmaR)/(Kepsi_(0)r^(2))`
    C
    `E=(sigmaR^(2))/(Kepsi_(0)r^(2))`
    D
    `E=(sigma^(2)R)/(Kepsi_(0)r^(2))`

  • The sun having surface temperature Ts radiates like a black body. The rasius of sun is Rs and earth is at a distance R from the surface of sun. Earth absorbs radiations falling on its surface from sun only and is at constant temperature T. If radiations falling on earth's surface are alomost parallel and earth also radiates like a blackbody, then

    A
    `T = T_(s) sqrt(R_(s)/(2R))`
    B
    `T = Ts`
    C
    `T = (T_(s))/(2) sqrt((R_(s)/(R ))`
    D
    `T = T_(s) sqrt((R_(s)/(R ))`

  • A body with surface area (A), temperature (T) and emissivity (e) = 0.6 is kept inside a spherical black body. What will be the maximum energy radiated ? [ sigma is Stefan's constant]

    A
    `0.2sigmaAT^(4)`
    B
    `0.4sigmaAT^(4)`
    C
    `0.6sigmaAT^(4)`
    D
    `0.8sigmaAT^(4)`
    • DISHA-THERMAL PROPERTIES OF MATTER-All Questions
    1. The total radiant energy per unit area, normal to the direction of inc...

      Text Solution

      |

    2. Three rods of same dimensions are arranged as shown in Fig. They have ...

      Text Solution

      |

    3. The sprinkling of wate slightly reduces the temperature of a closed ro...

      Text Solution

      |

    4. The specific heat capacity of a metal at low temperature (T) is given ...

      Text Solution

      |

    5. The emissive power of a black body at T=300K is 100Watt//m^(2) conside...

      Text Solution

      |

    6. A solid cube and a solid sphere of the same material have equal surfac...

      Text Solution

      |

    7. The density of water at 20^(@)"C is 998 kg/m"^(3) and at 40^(@)"C 992 ...

      Text Solution

      |

    8. A metallic rod l cm long, A square cm in cross-section is heated throu...

      Text Solution

      |

    9. If liquefied oxygen at 1 atmospheric pressure is heated from 50K to 30...

      Text Solution

      |

    10. If a bar is made of copper whose coefficient of linear expansion is on...

      Text Solution

      |

    11. A piece of ice falls from a height h so that it melts completely. Only...

      Text Solution

      |

    12. A body of mass 5 kg falls from a height of 20 metres on the ground and...

      Text Solution

      |

    13. Two straight metallic strips each of thickness t and length l are rive...

      Text Solution

      |

    14. The figure shows a system of two concentric spheres of radii r1 and r2...

      Text Solution

      |

    15. A block of steel heated to 100^(@)C is left in a room to cool Which of...

      Text Solution

      |

    16. Which of the following will expand the most for same rise in temperatu...

      Text Solution

      |

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

      Text Solution

      |

    18. When the temperature of a rod increases from t to r+Delta t, its momen...

      Text Solution

      |

    19. Two rods, one of aluminium and other made of steel, having initial len...

      Text Solution

      |

    20. A polished metal plate with a rough black spot on it is heated to abou...

      Text Solution

      |