[two waves] pass a point [every second]... The answer is in the question (B)
Energy of a wave:
E = nhc/λ
3000 = (n x 6.63 x 10⁻³⁴ x 3 x 10⁸)/(510 x 10⁻⁹)
n = 7.69 x 10 ²¹ photons per second per meter²
2.70 cm² = 2.70/10,000 m²
= 2.7 x 10⁻⁴
Photons per second = 7.69 x 10 ²¹ x 2.7 x 10⁻⁴
= 2.08 x 10¹⁸ photons per second
Answer:
When you toss a rolled up sock across the room, it travels faster as it becomes round and has more weight added on it and this causes the sock to travel in the direction you wish and this gives you a high chance of the sock going straight into the laundry basket, no matter how far away you are.
On the other hand, throwing a sock without rolling it up will cause the sock to just flat down as you throw it. It will travel at a low speed because it has no weight on it since it is flat, and if you try to throw it, it will atleast land 21 cm away from you. About a 0% chance of it getting in the basket.
Hope this helped! =>
