JEE Main · 2024 · 30 Jan 2024 · Shift 1 · Current Electricity

An electric toaster has resistance of

60Ω

at room temperature

(2 7^{\circ} C)

. 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

α = 2 \times 1 0^{- 4} /^{\circ} C

)

Answer: (C)

Solution

At 220 V and 2.75 A the resistance is

R_{T} = \frac{220}{2.75} = 80 Ω

.

Using

R_{T} = R_{0} [1 + α (T - 27)]

80 = 60 [1 + 2 \times 1 0^{- 4} (T - 27)]

\frac{80}{60} - 1 = 2 \times 1 0^{- 4} (T - 27) \Rightarrow \frac{1}{3} = 2 \times 1 0^{- 4} (T - 27)

T - 27 = \frac{1 0 ^{4}}{6} \approx 1667 \Rightarrow T \approx 169 4^{\circ} C

JEE Main · 2024 · 30 Jan 2024 · Shift 1 · Single correct option