A platinum resistance thermometer wire has a resistance of 70hms at 0°Cand 7.5 Ohms at 100°C. Calculate the temperature of the wire when the resistance is 7.2 Ohms
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
Correct Answer: Option B
Explanation:
R0 = 7Ω , R1 = 7.2 Ω, R2 = 7.5 Ω, Tx = ?
[(X – T100°C) ÷ (R1 - R0)] = [(T100°C – T0°C) ÷ (R2 - R0)]
[(Tx – 0) ÷ (72 – 7)] = [(100 – 0) ÷ (7.5 – 7)]
Tx/0.2 = (100 ÷ 0.5)
Tx = [(0.2 × 100)] ÷ 0.5
= 20/0.5 = 40°C
R0 = 7Ω , R1 = 7.2 Ω, R2 = 7.5 Ω, Tx = ?
[(X – T100°C) ÷ (R1 - R0)] = [(T100°C – T0°C) ÷ (R2 - R0)]
[(Tx – 0) ÷ (72 – 7)] = [(100 – 0) ÷ (7.5 – 7)]
Tx/0.2 = (100 ÷ 0.5)
Tx = [(0.2 × 100)] ÷ 0.5
= 20/0.5 = 40°C