Electromagnetic Radiation
Electromagnetic radiation of wavelength 300 nm has a certain energy per photon. How many photons of this radiation are needed to provide exactly 1 J of energy? (h = 6.626 × 10^-34 J·s, c = 3 × 10^8 m·s^-1)
Select the correct option:
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
More atomic structure Practice Questions
Bohr's atomic model successfully explains the hydrogen spectrum but fails for multi-electron atoms. ...
Bohr's atomic model successfully explains the hydrogen spectrum but fails for multi-electron atoms. ...
An element X has two naturally occurring isotopes: X-35 with 75% natural abundance and X-37 with 25%...
An element X has two naturally occurring isotopes: X-35 with 75% natural abundance and X-37 with 25%...
In a many-electron atom, the energy of the 4s orbital is lower than that of 3d in the ground state, ...
In a many-electron atom, the energy of the 4s orbital is lower than that of 3d in the ground state, ...
The radial probability distribution function 4πr^2 ψ^2 for a 2s orbital in hydrogen shows two maxima...
The radial probability distribution function 4πr^2 ψ^2 for a 2s orbital in hydrogen shows two maxima...
The radius of the first Bohr orbit for hydrogen is 0.529 Å. What would be the radius of the second o...
The radius of the first Bohr orbit for hydrogen is 0.529 Å. What would be the radius of the second o...
The energy of the electron in the ground state of the hydrogen atom is -2.18 × 10^-18 J. What is the...
The energy of the electron in the ground state of the hydrogen atom is -2.18 × 10^-18 J. What is the...
A proton and an alpha particle are both accelerated through the same potential difference V. What is...
A proton and an alpha particle are both accelerated through the same potential difference V. What is...
Which of the following statements correctly describes the shape and orientation of the p_z orbital r...
Which of the following statements correctly describes the shape and orientation of the p_z orbital r...
What is the minimum energy required in electron volts to completely remove an electron from the n=2 ...
What is the minimum energy required in electron volts to completely remove an electron from the n=2 ...
According to Hund's rule of maximum multiplicity, which electronic configuration represents the corr...
According to Hund's rule of maximum multiplicity, which electronic configuration represents the corr...
In a multi-electron atom, the effective nuclear charge Z_eff experienced by an electron in the 3p su...
In a multi-electron atom, the effective nuclear charge Z_eff experienced by an electron in the 3p su...
Which spectral series of hydrogen involves electron transitions to the n=3 level, and in which regio...
Which spectral series of hydrogen involves electron transitions to the n=3 level, and in which regio...
About This Question
- Subject
- chemistry
- Chapter
- atomic structure
- Topic
- electromagnetic radiation
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
1.51×1018
The energy of a single photon is given by E = hc/λ, where h is Planck's constant, c is the speed of light, and λ is the wavelength. This relationship shows that shorter wavelengths correspond to more energetic photons. Calculating the energy per photon: E = (6.626 × 10^-34 × 3 × 10^8) / (300 × 10^-9) = (1.988 × 10^-25) / (3 × 10^-7) = 6.626 × 10^-19 J per photon. To deliver a total energy of 1 J, the number of photons required = 1 / (6.626 × 10^-19) = 1.509 × 10^18 ≈ 1.51 × 10^18 photons. Option 4.52 × 10^18 corresponds to using λ = 900 nm, incorrectly tripling the wavelength. Option 6.02 × 10^18 is close to Avogadro's number, representing a conceptual confusion with mole calculations. Option 3.02 × 10^18 arises from using λ = 600 nm instead of 300 nm. This problem tests the photon energy formula E = hc/λ, a standard topic connecting electromagnetic radiation to quantum theory in JEE. Plausibility check: a UV photon at 300 nm carries about 4 eV (~6.6 × 10^-19 J), so ~1.5 × 10^18 such photons for 1 J is dimensionally and numerically consistent.
This medium difficulty chemistry question is from the chapter atomic structure, covering the topic of electromagnetic radiation. It appeared in the 2025 exam.
Looking for more practice? Explore all chemistry questions or browse atomic structure questions on RankGuru.