Question

At what temperature a gold ring of diameter 6.230 cm be heated so that it can be fitted on a wooden bangle of diameter 6.241 cm? Both the diameters have been measured at room temperature (27°C).
(Given: coefficient of linear thermal expansion of gold αL = 1.4 × 10-5 K-1)

• A. 125.7°C
• B. 91.7°C
• C. 425.7°C
• D. 152.7°C

Answer 1

Answer: (A)

125.7°C

Answer 2

The correct answer is (D) : 152.7°C
$ΔD = DαΔT$
$ΔT = \frac{0.011}{6.230 × 1.4 × 10^{-5}}$
= 126.11°C
$⇒ T_f = T \+ ΔT$
= (27 + 126.11)°C
= 153.11°C
Therefore , 153.11 is nearest to the 152.7