A spherical black body with a radius of \(12\) cm radiates \(450\) W power at \(500\) K. If the radius were halved and the temperature is doubled, the power radiated in watts would be:
1. \(450\)
2. \(1000\)
3. \(1800\)
4. \(225\)
We consider the radiation emitted by the human body. Which of the following statements is true:
1. | The radiation emitted is in the infrared region |
2. | The radiation is emitted only during the day |
3. | The radiation is emitted during the summers and absorbed during the winters |
4. | The radiation emitted lies in the ultraviolet region and hence is not visible |
Which of the following is closest to an ideal black body?
1. | Black lamp |
2. | Cavity maintained at a constant temperature |
3. | Platinum black |
4. | A lump of charcoal heated to high temperature |