As we know that speed of sounds is given as

here we know that
t = 23 degree C
now from above equation we will have


now we also know that distance between two consecutive resonance length is half of the wavelength



now we know that


so frequency will be 786 Hz
Answer:
b
Explanation:because endothermic contains heat so cookies need heat
Answer:
I already know the first one is electromagnetic but I don't know the second one sorry
Explanation:
Answer:
Temperature of the air in the balloon = 272°C
Explanation:
Given:
Volume of balloon = 500 m³
Air temperature = 15° C = 273 + 15 = 288 K
Total weight = 290 kg
Density of air = 1.23 kg/m³
Find:
Temperature of the air in the balloon
Computation:
Density of hot air = Density of air - [Total weight / Volume of balloon]
Density of hot air = 1.23 - [290 - 500]
Density of hot air = 0.65 kg/m³
[Density of hot air][Temperature of the air in the balloon] = [Density of air][Air temperature ]
Temperature of the air in the balloon = [(1.23)(288)]/(0.65)
Temperature of the air in the balloon = 544.98
Temperature of the air in the balloon = 545 K
Temperature of the air in the balloon = 545 - 273 = 272°C
The type of change is melting