Which one of the following is the correct relation between Celsius and Fahrenheit temperature scales? (Symbols carry their usual meanings)

The relationship between the Celsius (TC) and Fahrenheit (TF) temperature scales is defined by a linear equation based on the freezing and boiling points of water. On the Celsius scale, water freezes at 0°C and boils at 100°C, while on the Fahrenheit scale, these points are 32°F and 212°F respectively. This creates a ratio where 100 Celsius degrees are equivalent to 180 Fahrenheit degrees (a ratio of 5:9). To convert from Celsius to Fahrenheit, one must multiply the Celsius temperature by 9/5 (or 1.8) and then add 32 to account for the offset of the freezing point. Therefore, the correct mathematical relation is TF = 9/5 TC + 32. For example, 15°C converts to 59°F because (15 * 9/5) + 32 = 27 + 32 = 59.

Sources

1. [1] Exploring Society:India and Beyond ,Social Science-Class VII . NCERT(Revised ed 2025) > Chapter 2: Understanding the Weather > LET'S REMEMBER > p. 31