DPP – 11C22
Planks Quantum Theory & Electromagnetic Wave Theory
Q1. 100 watt monochromatic light λ = 400 nm. Calculate number of photons emitted per second by bulb.
(Ans: 2012 × 1017 per second)
Q2. If time period is 2 × 10–10 sec. Calculate λ, Frequency, wave number.
(Ans: ν = 5 × 109 sec-1 , λ = 6 × 10-2 m (0.06 m) , wave number = 16.66 𝑚−1 )
Q3. A 25 watt bulbs emits monochromatic yellow light of wavelength of 0.57 μm (micrometre). Calculate the rate of emission of quanta per second.
(Ans:7.18 × 1019 𝑠𝑒𝑐−1 )
Q4. Chlorophyll present in green leaves of plants absorbs light of 4.620 × 1014 Hz. Calculate the wavelength of radiation in nanometre. Which part of the electromagnetic spectrum does it belong to?
(Ans: 649.4 nm, visible range)