Answer : The wavelength of photon is, 
Explanation : Given,
Energy of photon = 
Formula used :
As, 
So, 
where,
= frequency of photon
h = Planck's constant = 
= wavelength of photon = ?
c = speed of light = 
Now put all the given values in the above formula, we get:
Conversion used : 
Therefore, the wavelength of photon is,
(20 N)/(2 m²) = (20/2) N/m² = 10 Pa
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The pascal (Pa) is the derived SI unit of pressure equal to 1 N/m².
<em>Given that:</em>
mass of the ball (m) = 0.5 Kg ,
ball strikes the wall (v₁) = 5 m/s ,
rebounds in opposite direction (v₂) = 2 m/s,
time duration (t) = 0.01 s,
<em> Determine the force (F) = ?</em>
We know that from Newton's II law,
<em>F = m. a</em> Newtons
(velocity acting in opposite direction, so <em>a = ( (v₁ + v₂)/t</em>
= m × (v₁ + v₂)/t
= 0.5 × (5 + 2)/0.01
= 350 N
<em>The force acting up on the ball is 350 N</em>
<span>The observation or measurement of physical properties of matter does not change its composition or its chemical nature. Other examples of physical properties include the infrared spectrum, attraction or repulsion to magnets, viscosity and opacity.</span>
