Current Electricity Question 18
Question 18 - 2024 (30 Jan Shift 1)
An electric toaster has resistance of $60 \Omega$ at room temperature $\left(27^{\circ} C\right)$. The toaster is connected to a $220 V$ supply. If the current flowing through it reaches $2.75 A$, the temperature attained by toaster is around : (if $\alpha=2 \times 10^{-4} /{ }^{\circ} C$ )
(1) $694^{\circ} C$
(2) $1235^{\circ} C$
(3) $1694^{\circ} C$
(4) $1667^{\circ} C$
Show Answer
Answer: (3)
Solution:
$R _{T=27}=60 \Omega, R _T=\frac{220}{2.75}=80 \Omega$
$R=R _0(1+\alpha \Delta T)$
$80=60\left[1+2 \times 10^{-4}(T-27)\right]$
$T \approx 1694^{\circ} C$
