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What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?
- a)2-0 eV, 2.5 * 101
- b)2*3 eV, 2.2 * 1011
- c)2.3 eV, 5.2 * 1110
- d)2.3 eV, 2.5 * 1010
Correct answer is option 'D'. Can you explain this answer?
Verified Answer
What is the energy of a typical visible photon? About how many photons...
The wavelength of visible light is between 400 and 700 nm. Thus we can take a typical visible wavelength to be
...(i)
The energy of a single photon is
...(ii)
Before we evaluate this, it is useful to note that the product he enters into many calculations and is a useful combination to remember. Since h has the dimension energy * time, he has the dimension energy * length and is conveniently expressed in eV-nm, as follows
or he = 1240 eV.nm ...(iii)
Putting numbers into (2), we find the energy for a typical visible photons to be
...(iv)
On the atomic level this energy is significant, but by everyday standards it is extremely small. When we look at the moon, the energy entering our eye per second is given by IA, where I is the intensity
and A is the area of the pupil 
if we take the diameter of the pupil to be about 6mm). Thus the number of photons entering our eye per second is number of photons per second 
photons per second This is such a large number that the restriction to integer numbers of photons is quite unimportant even for this weak source.
...(i)The energy of a single photon is
...(ii)Before we evaluate this, it is useful to note that the product he enters into many calculations and is a useful combination to remember. Since h has the dimension energy * time, he has the dimension energy * length and is conveniently expressed in eV-nm, as follows
or he = 1240 eV.nm ...(iii)
Putting numbers into (2), we find the energy for a typical visible photons to be
...(iv)On the atomic level this energy is significant, but by everyday standards it is extremely small. When we look at the moon, the energy entering our eye per second is given by IA, where I is the intensity
and A is the area of the pupil if we take the diameter of the pupil to be about 6mm). Thus the number of photons entering our eye per second is number of photons per second photons per second This is such a large number that the restriction to integer numbers of photons is quite unimportant even for this weak source.Most Upvoted Answer
What is the energy of a typical visible photon? About how many photons...
Energy of a typical visible photon:
- In order to determine the energy of a typical visible photon, we can use the equation E = hf, where E is the energy, h is Planck's constant (6.626 x 10^-34 J·s), and f is the frequency of the photon.
- Visible light has a range of frequencies, but we can consider the average wavelength of visible light to be around 550 nm (green light).
- Using the equation c = fλ, where c is the speed of light (3 x 10^8 m/s) and λ is the wavelength, we can calculate the frequency:
- f = c/λ = (3 x 10^8 m/s)/(550 x 10^-9 m) = 5.45 x 10^14 Hz
- Now we can calculate the energy of the photon using E = hf:
- E = (6.626 x 10^-34 J·s)(5.45 x 10^14 Hz) = 3.6 x 10^-19 J = 2.3 eV
Number of photons entering the eye per second when looking at the moon:
- The intensity of light is given as 3 x 10^-4 watts/m^2.
- Intensity is defined as the power per unit area, so we can calculate the total power entering the eye by multiplying the intensity by the area of the pupil of the eye.
- The approximate area of the pupil is typically considered to be 0.25 cm^2, which is equal to 2.5 x 10^-5 m^2.
- The power entering the eye is then given by:
- Power = Intensity x Area = (3 x 10^-4 watts/m^2)(2.5 x 10^-5 m^2) = 7.5 x 10^-9 watts
- Now we can calculate the number of photons entering the eye per second using the relationship between power and energy:
- Number of photons = Power / Energy = (7.5 x 10^-9 watts) / (2.3 x 10^-19 J) = 3.26 x 10^10 photons per second
Therefore, the correct answer is option D: 2.3 eV, 2.5 x 10^10.
- In order to determine the energy of a typical visible photon, we can use the equation E = hf, where E is the energy, h is Planck's constant (6.626 x 10^-34 J·s), and f is the frequency of the photon.
- Visible light has a range of frequencies, but we can consider the average wavelength of visible light to be around 550 nm (green light).
- Using the equation c = fλ, where c is the speed of light (3 x 10^8 m/s) and λ is the wavelength, we can calculate the frequency:
- f = c/λ = (3 x 10^8 m/s)/(550 x 10^-9 m) = 5.45 x 10^14 Hz
- Now we can calculate the energy of the photon using E = hf:
- E = (6.626 x 10^-34 J·s)(5.45 x 10^14 Hz) = 3.6 x 10^-19 J = 2.3 eV
Number of photons entering the eye per second when looking at the moon:
- The intensity of light is given as 3 x 10^-4 watts/m^2.
- Intensity is defined as the power per unit area, so we can calculate the total power entering the eye by multiplying the intensity by the area of the pupil of the eye.
- The approximate area of the pupil is typically considered to be 0.25 cm^2, which is equal to 2.5 x 10^-5 m^2.
- The power entering the eye is then given by:
- Power = Intensity x Area = (3 x 10^-4 watts/m^2)(2.5 x 10^-5 m^2) = 7.5 x 10^-9 watts
- Now we can calculate the number of photons entering the eye per second using the relationship between power and energy:
- Number of photons = Power / Energy = (7.5 x 10^-9 watts) / (2.3 x 10^-19 J) = 3.26 x 10^10 photons per second
Therefore, the correct answer is option D: 2.3 eV, 2.5 x 10^10.
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Community Answer
What is the energy of a typical visible photon? About how many photons...
The wavelength of visible light is between 400 and 700 nm. Thus we can take a typical visible wavelength to be
...(i)
The energy of a single photon is ...(ii)
Before we evaluate this, it is useful to note that the product he enters into many calculations and is a useful combination to remember. Since h has the dimension energy * time, he has the dimension energy * length and is conveniently expressed in eV-nm, as follows
or he = 1240 eV.nm ...(iii)
Putting numbers into (2), we find the energy for a typical visible photons to be
...(iv)
On the atomic level this energy is significant, but by everyday standards it is extremely small. When we look at the moon, the energy entering our eye per second is given by IA, where I is the intensity and A is the area of the pupil if we take the diameter of the pupil to be about 6mm). Thus the number of photons entering our eye per second is number of photons per second photons per second This is such a large number that the restriction to integer numbers of photons is quite unimportant even for this weak source.
...(i)The energy of a single photon is
...(ii)Before we evaluate this, it is useful to note that the product he enters into many calculations and is a useful combination to remember. Since h has the dimension energy * time, he has the dimension energy * length and is conveniently expressed in eV-nm, as follows
or he = 1240 eV.nm ...(iii)
Putting numbers into (2), we find the energy for a typical visible photons to be
...(iv)On the atomic level this energy is significant, but by everyday standards it is extremely small. When we look at the moon, the energy entering our eye per second is given by IA, where I is the intensity
and A is the area of the pupil if we take the diameter of the pupil to be about 6mm). Thus the number of photons entering our eye per second is number of photons per second photons per second This is such a large number that the restriction to integer numbers of photons is quite unimportant even for this weak source.
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What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer? for Physics 2025 is part of Physics preparation. The Question and answers have been prepared according to the Physics exam syllabus. Information about What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Physics 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer?.
What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer? for Physics 2025 is part of Physics preparation. The Question and answers have been prepared according to the Physics exam syllabus. Information about What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Physics 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer?.
Solutions for What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Physics.
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What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer?, a detailed solution for What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of What is the energy of a typical visible photon? About how many photons enter the eye per second when one looks at a weak source of light such as the moon, which produces light of intensity of about 3 * 10 -4 watts/m2?a)2-0 eV, 2.5 * 101b)2*3 eV, 2.2 * 1011c)2.3 eV, 5.2 * 1110d)2.3 eV, 2.5 * 1010Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an
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