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):
1. \(\dfrac{\sigma r^{2}T^{4}}{R^{2}}\)
2. \(\dfrac{\sigma r^{2}T^{4}}{4 \pi R^{2}}\)
3. \(\dfrac{\sigma r^{2}T^{4}}{R^{4}}\)
4. \(\dfrac{4\pi\sigma r^{2}T^{4}}{R^{2}}\)
1. | Both size gulab jamuns will get heated in the same time. |
2. | Smaller gulab jamuns are heated before bigger ones. |
3. | Smaller pizzas are heated before bigger ones. |
4. | Bigger pizzas are heated before smaller ones. |