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Class 12 Dual Nature of Radiation and Matter worksheet
CBSE Physics. Photoelectric effect, work function, stopping potential, photons, de Broglie wavelength. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The energy of a photon of wavelength 125 nm is: (hc = 1240 eV nm)
- 0.10 eV
- 9.92 eV
- 4.96 eV
- 99.2 eV
Answer
(b) 9.92 eV
E = hc/λ
- 2.
Light of wavelength 160 nm falls on nickel (work function 5.15 eV). The stopping potential is: (hc = 1240 eV nm)
- 12.9 V
- 5.15 V
- 7.75 V
- 2.6 V
Answer
(d) 2.6 V
eV₀ = hc/λ − φ = 7.75 − 5.15
- 3.
The threshold wavelength for potassium (work function 2.3 eV) is: (hc = 1240 eV nm)
- 269.57 nm
- 1,078.26 nm
- 2,852 nm
- 539.13 nm
Answer
(d) 539.13 nm
λ₀ = hc/φ
Section B · short answer
- 4.
A 4 mW laser emits light of wavelength 310 nm. How many photons does it emit each second? (hc = 1240 eV nm) (e = 1.6 × 10⁻¹⁹ C)
Answer
6.25 × 10¹⁵
E = 4 eV = 4 × 1.6 × 10⁻¹⁹ J; n = P/E
- 5.
Light of wavelength 500 nm falls on caesium (φ = 2.14 eV). Find the largest kinetic energy of the photoelectrons and the stopping potential. (hc = 1240 eV nm)
Answer
0.34 eV; 0.34 V
E = 2.48 eV; K = E − φ
Section C · long answer
- 6.
Ultraviolet or visible light of wavelength 200 nm falls on calcium, whose work function is 3.2 eV. Find the photon energy, the largest kinetic energy of the electrons, the stopping potential and the threshold wavelength. (hc = 1240 eV nm)
Answer
6.2 eV; 3 eV; 3 V; 387.5 nm
E = hc/λ; K = E − φ; V₀ = K/e; λ₀ = hc/φ
Fresh sheets for your child
In the app, every Dual Nature of Radiation and Matter sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
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