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  1. The rate of energy emitted by a black body is governed by the Stefan-Boltzmann law, which states that the energy radiated per unit area is proportional to the fourth power of the temperature: E ∝ T⁴ So, for a black body at a temperature of 300 K, the energy emitted will be proportional to: 300⁴ ThusRead more

    The rate of energy emitted by a black body is governed by the Stefan-Boltzmann law, which states that the energy radiated per unit area is proportional to the fourth power of the temperature:

    E ∝ T⁴

    So, for a black body at a temperature of 300 K, the energy emitted will be proportional to:

    300⁴

    Thus, the correct answer is: 300⁴

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  2. The Stefan-Boltzmann law states that the brightness of an object depends on its temperature and emissivity. Black objects have the highest emissivity, meaning they can emit and absorb radiation more efficiently than grey or white objects. Since all objects can withstand the same maximum temperatureRead more

    The Stefan-Boltzmann law states that the brightness of an object depends on its temperature and emissivity. Black objects have the highest emissivity, meaning they can emit and absorb radiation more efficiently than grey or white objects.

    Since all objects can withstand the same maximum temperature of 2,800°C, the black object will glow the brightest because it has the highest emissivity and thus radiates energy more efficiently.

    So, the correct answer is: the black object

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  3. Transmittance describes the amount of heat radiation received by a material divided by that amount received. Transmittance is how much radiation can transmit through the surface of the body compared to its incidence on a body. In this context, the right term is: Transmittance

    Transmittance describes the amount of heat radiation received by a material divided by that amount received.
    Transmittance is how much radiation can transmit through the surface of the body compared to its incidence on a body.

    In this context, the right term is: Transmittance

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  4. To determine the ratio of the surface temperatures of the Sun and star X, we use Wien's displacement law: λₘₐₓ * T = b where: - λₘₐₓ is the wavelength at which the emission is maximum, - T is the temperature of the body, - b is Wien's constant (b = 2.898 × 10⁻³ m K). Thus, from this law, the temperaRead more

    To determine the ratio of the surface temperatures of the Sun and star X, we use Wien’s displacement law:

    λₘₐₓ * T = b

    where:

    – λₘₐₓ is the wavelength at which the emission is maximum,
    – T is the temperature of the body,
    – b is Wien’s constant (b = 2.898 × 10⁻³ m K).

    Thus, from this law, the temperature of each star can be derived as follows:

    T = b / λₘₐₓ

    For the Sun:
    Tₛᵤₙ = (2.898 × 10⁻³) / (510 × 10⁻⁹) = 5688 K

    For star X:
    Tₓ= (2.898 × 10⁻³) / (350 × 10⁻⁹) = 8271 K

    Now, the ratio of the surface temperatures is :

    Tₛᵤₙ / Tₓ = 5688 / 8271 ≈ 0.688

    Hence, the correct answer is: 0.68

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