Question

During photosynthesis in a leaf, red light is absorbed. Calculate the energy of a red-light photon with a wavelength of 700. nm.

a) 2.84 x 10^19 J
b) 4.27 x 10^-19 J
c) 5.66 x 10^19 J
d) 8.52 x 10^-19 J

Answer 1

Therefore, the energy of a red-light photon with a wavelength of 700 nm is approximately 2.84 x 10-19 joules, which corresponds to choice (b).

Step-by-step explanation:

The question pertains to calculating the energy of a red-light photon during photosynthesis in a leaf, given the wavelength is 700 nm (nanometers). To calculate the energy of a photon, we use the formula:

E = rac{hc}{λ}

Where:

• E is the energy of the photon in joules (J)
• h is Planck's constant (6.626 x 10-34 J·s)
• c is the speed of light in a vacuum (3.00 x 108 m/s)
• λ (lambda) is the wavelength of the light in meters

First, we need to convert the wavelength from nanometers to meters by multiplying 700 nm by 10-9 (since there are 1 billion nanometers in a meter). Thus, λ = 700 x 10-9 m.

Now, we can plug the values into the equation:

E = rac{(6.626 x 10-34 J·s)(3.00 x 108 m/s)}{700 x 10-9 m}

After calculating, we get:

E ≈ 2.84 x 10-19 J

The energy of a red-light photon with a wavelength of 700 nm is approximately 2.84 x 10^-19 joules, calculated using the formula that incorporates Planck's constant and the speed of light.