🚀 Fun Fact: Did you know our Sun is an example of a black body? Let's dive into some interesting physics behind this concept!

• Two cool scientists, Stefan and Boltzmann, figured out a law (both coming at it from different directions) about how black bodies release energy.
• A black body is a theoretical object that absorbs all light and radiation thrown its way and then emits this energy.
• This law talks about the total power (luminosity) L given out by this body.

• L = σAT⁴
  • L = Total power radiated
  • A = Surface area of the black body
  • T = Absolute temperature (in Kelvin, K)
  • σ = Stefan–Boltzmann constant = 5.67 × 10⁻⁸ Wm⁻² K⁻⁴

✨ Quick Note: Power = energy radiated every second. So, a square metre of a black body emits σT⁴ energy every second.

🌍 Real-world Example: Ever felt the warmth of sunlight on your skin? The sun radiates energy, and using Stefan's law, we can find out how much energy it releases!

• Light Bulbs & Spectrophotometers: A student found that two lamps (let's call them A and B) have different peak intensities at different wavelengths. Can you guess their temperatures?
  • Using the data, TA = 2400K, TB = 2100K.
  • With equal surface areas, Lamp A radiates 1.7 times the power of Lamp B.
• Hot Plate Drama: A hot plate at 150°C in a 20°C room behaves like a black body.
  • Net power exchanged = 35W. (It's giving off more energy than it's absorbing)
• The Sun's Power Show
  • Power from 1m² of the Sun = 6.4 × 10⁷ W.
• In one day, the Sun belts out a whopping 3.4 × 10³1 J energy! That’s a lot of sunscreen.