NEET2026PhysicsChapterActual
A nichrome heating element has a resistance of 100 at room temperature ( 20^ C ). When it is connected to a 220 V supply, a steady current of 2.0 A flows through it. If the temperature coefficient of resistance of nichrome averaged over the temperature range involved is 2.0 10⁻⁴ ^ C ⁻¹ , what is the steady temperature of the heating element?
Options
- A500^ C
- B480^ C
- C520^ C
- D70^ C
Correct answer
C. 520^ C
Step-by-step solution
Resistance at room temperature T₁ = 20^ C is R₁ = 100 . Resistance at steady temperature T₂ is R₂ = V I = 220 2.0 = 110 . Using the relation R₂ = R₁ [1 + (T₂ - T₁)] , we get: 110 = 100 [1 + 2.0 10⁻⁴ (T₂ - 20)] 1.1 = 1 + 2.0 10⁻⁴ (T₂ - 20) 0.1 = 2.0 10⁻⁴ (T₂ - 20) T₂ - 20 = 0.1 2.0 10⁻⁴ = 500 T₂ = 520^ C Answer: 520^ C