Microwave radiation is absorbed by the water in food. As the water absorbs the heat it causes the food to get hot. If the wavelength of a microwave is 10, calculate the frequency and the energy of each photon.

1) The frequency of each photon is 3.0 × 10⁹ Hz

2) The energy of each photon is 1.98786 × 10⁻²⁴ J

Explanation:

The energy, 'E', in a photon of light is given by Planck's equation as follows;

E = h·f = h·c/λ

Where;

E = The energy of a photon

h = Planck constant = 6.6262 × 10⁻³⁴ J·s

f = The frequency of the photon/radiation

c = The speed of light = 3.0 × 10⁸ m/s

λ = The wavelength of the photon/radiation

The given parameters of the microwave are;

The wavelength, λ = 10 cm = 0.1 m

The type of wave = Microwave

1) From E = h·f = h·c/λ, we find that the frequency, 'f' equals c/λ

∴ f = 3.0 × 10⁸ m/s/(0.1 m) = 3.0 × 10⁹ 1/s = 3.0 × 10⁹ Hz

The frequency of each photon, f = 3.0 × 10⁹ Hz

2) From E = h·f = h·c/λ, the energy, 'E', of each photon is given as follows;

E = h·c/λ = 6.6262 × 10⁻³⁴ J·s × 3.0 × 10⁸ m/s/(0.1 m) = 1.98786 × 10⁻²⁴ J

The energy of each photon, E = 1.98786 × 10⁻²⁴ J

- lead + phosphoric acid = hydrogen + lead(ii) phosphate

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml