A platinum resistance thermometer reads 5 $\Omega$ at the ice point and 5.23 $\Omega$ at the steam point. In a hot bath its resistance is 5.795 $\Omega$. Assuming a linear variation, the temperature of the bath is about

1. With a linear scale, $t = \dfrac{R_t - R_0}{R_{100} - R_0} \times 100$. 2. Numerator: $5.795 - 5 = 0.795\ \Omega$. 3. Denominator: $5.23 - 5 = 0.23\ \Omega$. 4. $t = (0.795/0.23)\times 100 \approx 346\ ^\circ\text{C}$. The lower options come from misreading the ice/steam interval. _Source: NCERT Class 12 Physics Ch 3 "Current Electricity", p.11_