A boy seeing a lighting starts counting seconds, until he hears thunder. He then claims to have found an approximate but simple rule that if count of second is divided by an integer, the result directly gives the distance of lighting source in km. What is the integer. Take sound velocity as $$330$$ $$m/s$$.

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Infinity Learn · Accepted Answer

For N seconds, sound will travel a distanceℓ$$=vsound$$ ×Nℓ$$($$ in km $$)=330$$×$$N1000km$$ℓin $$km=N1000/330$$≃$$N3Integer$$ $$=$$ $$3$$

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A boy seeing a lighting starts counting seconds, until he hears thunder. He then claims to have found an approximate but simple rule that if count of second is divided by an integer, the result directly gives the distance of lighting source in km. What is the integer. Take sound velocity as 330 m/s.

For N seconds, sound will travel a distance
$ℓ = v_{sound} \times N$
$ℓ (in km) = \frac{330 \times N}{1000} km$
$ℓ (in km) = \frac{N}{1000 / 330} ≃ \frac{N}{3}$
Integer = 3

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For N seconds, sound will travel a distanceℓ=vsound ×Nℓ( in km )=330×N1000kmℓin km=N1000/330≃N3Integer = 3

Ready to Test Your Skills?

free study material

For N seconds, sound will travel a distance
$ℓ = v_{sound} \times N$
$ℓ (in km) = \frac{330 \times N}{1000} km$
$ℓ (in km) = \frac{N}{1000 / 330} ≃ \frac{N}{3}$
Integer = 3