Question

Q.2.
A substance absorbs 2.0 x 1016 quanta or radiations per second and 0.002 mole of it reacts in 1200 seconds. What is the quantum yield or the reaction (N =
6.02 x 1023)?
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Answer 1

It has given that, number of photons absorbs per second = 2 × 10^16 and 0.002 mole of it reacts in 1200 seconds.

We have to find the quantum yield.

solution : quantum yield = number of photons emitted/no of photons absorbed.

Here number of photons emitted = no of moles of it reacts in 1200 sec × Avogadro's number

= 0.002 × 6.022 × 10²³

= 12.044 × 10²⁰ ≈ 12 × 10²⁰

Now number of photons absorbed = number of photons absorbed per second × 1200 seconds

= 2 × 10^16 × 1200

= 24 × 10^18

Now, quantum yield = (12 × 10^20)/(24 × 10^18) = (1200)/24 = 50

therefore quantum yield or the reaction is 50