A nichrome heating element has resistance 75.3 $\Omega$ at 27.0 °C. Co…

Question

A nichrome heating element has resistance 75.3 $\Omega$ at 27.0 °C. Connected to a 230 V supply it draws a steady current of 2.68 A. Taking $\alpha = 1.70 	imes 10^{-4}\ ^\circ	ext{C}^{-1}$, the steady temperature of the element is about

Accepted Answer

C. 847 °C

1. Steady resistance: $R_2 = 230/2.68 = 85.8\ \Omega$.
2. Use $R_2 = R_1[1 + \alpha(T_2 - T_1)]$.
3. $T_2 - T_1 = (85.8 - 75.3)/(75.3 	imes 1.70	imes10^{-4}) = 820\ ^\circ	ext{C}$.
4. $T_2 = 820 + 27.0 = 847\ ^\circ	ext{C}$. Smaller values arise from using the wrong reference resistance.
_Source: NCERT Class 12 Physics Ch 3 "Current Electricity", p.10_

Answer

320 °C

Answer

560 °C

Answer

1100 °C

A nichrome heating element has resistance 75.3 $\Omega$ at 27.0 °C. Connected to a 230 V supply it draws a steady current of 2.68 A. Taking $\alpha = 1.70 \times 10^{-4}\ ^\circ\text{C}^{-1}$, the steady temperature of the element is about