If the temperature of a black body increases from $7^{\circ}C$ to $287^{\circ}C$,then what is the ratio of the rate of energy emission?

Suppose the sun expands so that its radius becomes $100$ times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it then will increase by a factor of

$A$ black body radiates energy at the rate of $1 \times 10^5 \ J/s \cdot m^2$ at a temperature of $227^\circ C$. The temperature to which it must be heated so that it radiates energy at a rate of $1 \times 10^9 \ J/s \cdot m^2$ is:

$A$ black body radiates $20\,W$ at temperature $227^{\circ}C$. If the temperature of the black body is changed to $727^{\circ}C$,then its radiating power will be ..... $W$.

If the radius of a star is $R$ and it acts as a black body,what would be the temperature of the star,in which the rate of energy production is $Q$? ($\sigma$ stands for Stefan's constant)

The rate of radiation by a black body is $R$ at temperature $T$. Another body has the same area but an emissivity of $0.2$ and a temperature of $3T$. Its rate of radiation is: