Physics
Heat
Easy

Question

The radiation emitted by a star A is 1000 times that of the sun. If the surface temperatures of the sun and star A are 6000 K and 2000 K respectively, the ratio of the radii of the star A and the sun is:

  1. 300:1
  2. 600:1
  3. 900:1
  4. 1200:1

The correct answer is: 900:1


    Related Questions to study

    Heat
    Physics

    The temperature of a body is increased by 50%. The 4amount of radiation emitted by it would be nearly

    The temperature of a body is increased by 50%. The 4amount of radiation emitted by it would be nearly

    PhysicsHeat
    Heat
    Physics

    A black body is heated from 7oC to 287oC. The ratio of radiation emitted is:

    A black body is heated from 7oC to 287oC. The ratio of radiation emitted is:

    PhysicsHeat
    Heat
    Physics

    The rate of dissipation of heat by a black body at temperature T is Q. What will be the rate of dissipation of heat  by another body at temperature 2T and emissivity 0.25?

    The rate of dissipation of heat by a black body at temperature T is Q. What will be the rate of dissipation of heat  by another body at temperature 2T and emissivity 0.25?

    PhysicsHeat
    parallel
    Heat
    Physics

    A black body at a high temperature TK radiates energy at the rate of EW/m2. When the temperature falls to (T/2) K, the radiated energy will be:

    A black body at a high temperature TK radiates energy at the rate of EW/m2. When the temperature falls to (T/2) K, the radiated energy will be:

    PhysicsHeat
    Heat
    Physics

    Two identical long, solid cylinders are used to conduct heat from temp T1 to temp T2. Originally the cylinders are connected in series and the rate of heat transfer is H. If the cylinders are connected in parallel then the rate of heat transfer would be:

    Two identical long, solid cylinders are used to conduct heat from temp T1 to temp T2. Originally the cylinders are connected in series and the rate of heat transfer is H. If the cylinders are connected in parallel then the rate of heat transfer would be:

    PhysicsHeat
    Heat
    Physics

    Three rods made of the same material and having the same cross section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at 0°C and 90°C respectively. The temperature of the junction of the three rods will be

    Three rods made of the same material and having the same cross section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at 0°C and 90°C respectively. The temperature of the junction of the three rods will be

    PhysicsHeat
    parallel
    Heat
    Physics

    If l is the length, A is the area of cross-section and K the thermal conductivity, then the thermal resistance of the block is given by

    If l is the length, A is the area of cross-section and K the thermal conductivity, then the thermal resistance of the block is given by

    PhysicsHeat
    Heat
    Physics

    The ratio of the densities of the two bodies is 3:4 and the ratio of specific heats is 43. Find the ratio of their thermal capacities for unit volume?

    The ratio of the densities of the two bodies is 3:4 and the ratio of specific heats is 43. Find the ratio of their thermal capacities for unit volume?

    PhysicsHeat
    Heat
    Physics

    Two bars of thermal conductivities K and 3K and lengths 1 cm and.2 cm respectively have equal cross-sectional area, they are joined lengths wise as shown in the figure.
    If the temperature at the ends of this composite bar is 0°C and Kll respectively (see figure), then the temperature phi of the interface is

    Two bars of thermal conductivities K and 3K and lengths 1 cm and.2 cm respectively have equal cross-sectional area, they are joined lengths wise as shown in the figure.
    If the temperature at the ends of this composite bar is 0°C and Kll respectively (see figure), then the temperature phi of the interface is

    PhysicsHeat
    parallel
    Heat
    Physics

    Calculate the amount of heat (in calories) required to convert 5 gm of ice at 0°C to steam at 100°C

    Calculate the amount of heat (in calories) required to convert 5 gm of ice at 0°C to steam at 100°C

    PhysicsHeat
    Heat
    Physics

    One kilogram of ice at 0o C is mixed with one kilogram of water at 80oC. The final temperature of the mixture is (Take specific heat of water=4200Jkg-1K-1 , Latent heat of ice=336KJ/kg-1)

    One kilogram of ice at 0o C is mixed with one kilogram of water at 80oC. The final temperature of the mixture is (Take specific heat of water=4200Jkg-1K-1 , Latent heat of ice=336KJ/kg-1)

    PhysicsHeat
    Heat
    Physics

    The root mean square speed of hydrogen molecules at a certain temperature is 300m/s. If the temperature is doubled and hydrogen gas dissociates into atomic hydrogen, the rms speed will become:

    The root mean square speed of hydrogen molecules at a certain temperature is 300m/s. If the temperature is doubled and hydrogen gas dissociates into atomic hydrogen, the rms speed will become:

    PhysicsHeat
    parallel
    Heat
    Physics

    The temperature of an ideal gas is increased from 120K to 480K. If at 120K, the root mean square speed of the gas molecules is ‘v’, then at 480K it will be

    The temperature of an ideal gas is increased from 120K to 480K. If at 120K, the root mean square speed of the gas molecules is ‘v’, then at 480K it will be

    PhysicsHeat
    Heat
    Physics

    At room temperature (270C) the ‘rms’ speed of the molecules of a certain diatomic gas is found to be 1920 ms-1. The gas is

    At room temperature (270C) the ‘rms’ speed of the molecules of a certain diatomic gas is found to be 1920 ms-1. The gas is

    PhysicsHeat
    Heat
    Physics

    The mass of an oxygen molecule is about 16 times that of a hydrogen molecule. At room temperature the ‘rms’ speed of oxygen molecules is v. The ‘rms’ speed of the hydrogen molecules at the same temperature will be

    The mass of an oxygen molecule is about 16 times that of a hydrogen molecule. At room temperature the ‘rms’ speed of oxygen molecules is v. The ‘rms’ speed of the hydrogen molecules at the same temperature will be

    PhysicsHeat
    parallel

    card img

    With Turito Academy.

    card img

    With Turito Foundation.

    card img

    Get an Expert Advice From Turito.

    Turito Academy

    card img

    With Turito Academy.

    Test Prep

    card img

    With Turito Foundation.