Q18.The disintegration rate of a certain radioactive sample at any instant is 4250 disintegrations per minute. 10 minutes later, the rate becomes 2250 disintegrations per minute. The approximate decay constant is (Take loge 1. 88 = 0. 63 ) (1) 0. 02 min−1 (2) 2. 7 min−1 (3) 0. 063 min−1 (4) 6. 3 min−1
What This Question Tests
This question requires calculating the energy of a single photon and then using the given intensity to find the number of photons crossing a unit area per second.
Concepts Tested
Formulas Used
E = hc/λ
Intensity = (Number of photons per unit area per unit time) × Energy per photon
📚 NCERT Sections This Tests
12.5 — A Hydrogen Atom Initially In The Ground Level Absorbs A Photon,
Physics Class 12 · Chapter 12
12.5 A hydrogen atom initially in the ground level absorbs a photon, which excites it to the n = 4 level. Determine the wavelength and frequency of photon.
11.4 — Monochromatic Light Of Wavelength 632.8 Nm Is Produced By A
Physics Class 12 · Chapter 11
11.4 Monochromatic light of wavelength 632.8 nm is produced by a helium-neon laser. The power emitted is 9.42 mW. (a) Find the energy and momentum of each photon in the light beam, (b) How many photons per second, on the average, arrive at a target irradiated by this beam? (Assume the beam to have uniform cross-section which is less than the target area), and (c) How fast does a hydrogen atom have to travel in order to have the same momentum as that of the photon?
12.3 — A Difference Of 2.3 Ev Separates Two Energy Levels In An Atom. What
Physics Class 12 · Chapter 12
12.3 A difference of 2.3 eV separates two energy levels in an atom. What is the frequency of radiation emitted when the atom make a transition from the upper level to the lower level?
📋 Question Details
- Chapter
- Dual Nature of Matter
- Topic
- Photon Energy and Intensity
- Year
- 2022
- Shift
- 26 Jul Shift 1
- Q Number
- Q18
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 11: Dual Nature of Radiation and Matter
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