Convert 25°C to Kelvin.

• A. 298.15 K
• B. 273.15 K
• C. 303.15 K
• D. 571.15 K

Answer: (A)

Converting Celsius to Kelvin uses the simple rule: add 273.15. That’s because the Kelvin scale starts at absolute zero and has the same degree size as Celsius.

So for 25°C, you add 273.15: 25 + 273.15 = 298.15 K. That matches the given value.

273.15 K corresponds to 0°C, and 303.15 K corresponds to 30°C. 571.15 K corresponds to 298°C, which is far from 25°C.