The heat (energy) needed to raise the temperature of the water is given by

The wavelength of the radiation of the oven is

, so the energy of a single photon of this radiation is

So, the number of photons required to heat the water is the total energy absorbed by the water divided by the energy of a single photon:

photons
Answer:
<u><em>0.03 m/s</em></u>
Explanation:
<em>Applying law of conservation of momentum, </em>
- <em>m₁v₁ + m₂v₂ = (m₁ + m₂)v</em>
- <em>0.105(24) + 75(0) = (0.105 + 75)v</em>
- <em>75.105v = 2.52</em>
- <em>v = 2.52/75.105</em>
- <em>v = </em><u><em>0.03 m/s</em></u>