What is the equivalent of 20K in Celsius scale?

Analysis

The question asks for the conversion of a temperature value from the Kelvin (K) scale to the Celsius (°C) scale.

Concept

The relationship between the Kelvin scale and the Celsius scale is defined by the following formula:

In most JAMB and secondary school physics contexts, we use the approximation:

Solution

1. Identify the given value: $T(\text{K}) = 20\text{K}$
2. Apply the formula: $T(^\circ\text{C}) = 20 - 273$
3. Calculate the result: $20 - 273 = -253$

Therefore, 20K is equivalent to $-253^\circ\text{C}$.

Conclusion

Comparing our result to the provided options, it matches option A.

Tip

Always remember that the Kelvin scale is an "absolute scale," meaning it cannot have negative values (0K is absolute zero). When converting from Kelvin to Celsius, you subtract 273; when converting from Celsius to Kelvin, you add 273. A simple way to remember this is: "K is for Kelvin, and Kelvin is 'Kooler' (higher in value), so you add to get to Kelvin and subtract to get to Celsius."