How many zlings in your plodge?

Friday 28 September 2018

If an electron is accelerated through a potential difference of 1V it will gain a kinetic energy of 1 eV. How much kinetic energy will an electron gain if accelerated through a potential difference of 5V?

If one apple costs 1 Euro, how much do 5 apples cost?

The questions are essentially the same but students find the first one much more difficult and anyone who hasn't studied physics would be completely baffled, it might as well be in another language and that might be the key. We need to understand the words before trying to read sentences.

To be fair the two questions are not the same, one is very direct the other is rather roundabout, maybe the apple question should be more like this:

If a man has 1 Euro he could buy 1 apple. How many apples could a man buy if he was given 5 Euros?

And if we remove the familiar language:

If a Martian has 1 zling in his plodge he could obtain 1 plob. How many plobs could he obtain if he had 5 zlings in his plodge?

Working the other way, if we simplify the Physics question we get:

If 1 eV requires 1Volt how many Volts are required for 5 eV.

Easy to answer with no knowledge of physics and that was of course the point of the first question. It tests and understanding of physics concepts rather than the ability to do simple maths.


Tags: TOK