For the following question, two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the c
orrect answer to these questions from the codes (i), (ii), (iii) and (iv) as given below. i) Both A and R are true and R is correct explanation of the assertion. ii) Both A and R are true but R is not the correct explanation of the assertion. iii) A is true but R is false. iv)A is false but R is true. Assertion: Concave mirrors are used as reflectors in torches, vehicle head-lights and in search lights. Reason: When the object is placed beyond the centre of curvature of a concave mirror, the image formed is real and inverted.
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1 answer:
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Answer:
i)20369 photons
ii) 40 ps
Explanation:
Momentum of one Sodium atom:
In other to stop it, it must absorb the same momentum in photons:
Now, for the minimun time, we use the speed of light and the wavelength. For the n photons: