Answer:
It's really important waves type for fulfill human's needs
Explanation:
Electromagnetic waves are transverse waves composed by the perpendicular oscillating electric and magnetic fields.
EM waves have both Electrical and magnetic features.
they travel in the velocity of light (3*10⁸ ms⁻¹)
they does not require any media to travel. It has two perpendicular electric field and the magnetic field which are perpendicular to each other
They travel perpendicular to each of those electric and magnetic fields.
Example :
- Radio Wave
- Micro Wave
- IR wave
- Light Wave
- UV rays
- X rays
- Gamma rays
- Cosmic rays
The main importance of em waves is they allow energy to be stored within them and then can be propagated over a large distance using the dielectric and magnetic properties of materials .
This performance has been used in many fields wisely and effectively to make the things easy.
Ex : medicine , Telecommunication , energy , Engineering etc
<span>step 1: energy required to heat coffee
E = m Cp dT
E = energy to heat coffee
m = mass coffee = 225 mL x (0.997 g / mL) = 224g
Cp = heat capacity of coffee = 4.184 J / gK
dT = change in temp of coffee = 62.0 - 25.0 C = 37.0 C
E = (224 g) x (4.184 J / gK) x (37.0 C) = 3.46x10^4 J
step2: find energy of a single photon of the radiation
E = hc / λ
E = energy of the photon
h = planck's constant = 6.626x10^-34 J s
c = speed of light = 3.00x10^8 m/s
λ = wavelength = 11.2 cm = 11.2 cm x (1m / 100 cm) = 0.112 m
E = (6.626x10^-34 J s) x (3.00x10^8 m/s) / (0.112 m) = 1.77x10^-16 J
step3: Number of photons
3.46x10^4 J x ( 1 photon / 1.77x10^-16 J) = 1.95x10^20 photons</span>
Larger mass creates a stronger pull
