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Value of a One Rupee Coin

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I was scratching my recharge card with a one rupee coin when my sister appeared out of nowhere, and asked, ‘I am your sister, so how much money will you give me in this Dashain?’ It was quick, and as I processed that query slowly in my mind, I could see that her eyebrows were raised, her eyes bulged, and her lips and palms perfectly synchronized to mean “HOW MUCH?”.

I was in a trap !

Unlike Tihar, Dashain is quite difficult for brothers. You just give something without expecting anything in return. But I had a plan.

‘This coin is for you’, I handed her the one rupee coin. She was like ‘I deserve more’.

With a discontented expression she said, ‘It has no value. Can’t even buy a chocolate.’


I got a point, and that was all I needed. As usual, I began my lecture.

‘Present world’s energy consumption is so large that we are soon going to endure its crisis. You definitely might have heard about the most famous equation by Albert Einstein, E = mc². So, let’s not forget its significance when we call something worthless.  Come, let’s make some calculations’. We moved towards the whiteboard.

‘Let’s assume the mass of the coin to be 5 grams.
And, as c is the speed of light,

We get,

E=4.5\times { 10 }^{ 14 } Joules.

Burning one gallon (3.785 liters) of gasoline releases E=1.3\times { 10 }^{ 8} Joules of energy. So, the energy in this coin is nearly equal to the energy released by burning 3.5 million gallons of gasoline. This would provide all the energy requirements for a million people for a day. This is immense, and you are saying it has no value.’

She didn’t respond. She was closely observing me, and that sarcastic smile on her face just meant one thing – I was behaving mad!

I felt like a cat disguised as a tiger when I had to admit that, ‘the energy we just discussed is the mass energy, not the chemical energy and the present world has no any methods to convert mass-energy into useful work energy’.

She immediately felt victorious.

‘Think like a Physicist. There is, at least, some satisfaction.’ I had to defend.

I hardly believed she understood everything, until she gave me the same lecture when I wasn’t picking up an exchanged coin in a grocery store a week later.

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Sandesh Parajuli

Sandesh Parajuli

Sandesh is a founder of Cherrubics. He is an undergraduate aerospace major at Department of Mechanical and Aerospace Engineering, Pulchowk Campus, Nepal.

2 Responses

  1. The short story was quite fun to read because of the critical thinking involved in the interaction between siblings. AND there was hint of hypocrisy in the character of narrator because he doesn’t really believe that a coin values in reality unlike he said it could in front of his sister. Which was why he didn’t care to pick up the coin in grocery store.
    So, this concluded that eventually a coin doesn’t value greatly and the first question of sister asking about how much money she will be getting was argued wrongly , right?

    1. Your analysis was truly impressive ! Indeed, the entire scene builds up in subtle hypocrisy and the narrator has accepted it when he said that he ‘felt like a cat disguised as a tiger’. However, it was written purely with a basic scientific intention rather than to reinforce any philosophical ideology. In that light, the argument is completely valid and would not have changed even if the subject was a counterfeit coin, which even the non-hypocritical narrator would consciously choose not pick given the opportunity.

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