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A 100-W lightbulb has a resistance of about 12 Ω when cold (20 ∘C) and 136 Ω when on (hot). Estimate the temperature of the filament when hot assuming an average temperature coefficient of resistivity α=0.0045(C)−1.
A 100-W lightbulb has a resistance of about 12 Ω when cold (20 ∘C) and 136 Ω when on (hot). Estimate the temperature of the filament when hot assuming an average temperature coefficient of resistivity α=0.0045(C)−1.
A 100-W lightbulb has a resistance of about 12 Ω when cold (20 ∘C) and 152 Ω when on (hot). Estimate the temperature of the filament when hot assuming an average temperature coefficient of resistivity α=0.0045(C)−1.
A 100-W lightbulb has a resistance of about 12 Ω when cold (20 ∘C) and 124 Ω when on (hot). Estimate the temperature of the filament when hot assuming an average temperature coefficient of resistivity α=0.0045(C)−1.
A 100-W lightbulb has a resistance of about 12 Ω when cold (20 ∘C) and 128 Ω when on (hot). Estimate the temperature of the filament when hot assuming an average temperature coefficient of resistivity α=0.0045(C)−1.
A 100-W lightbulb has a resistance of about 12 Ω when cold (20 ∘C) and 128 Ω when on (hot). Estimate the temperature of the filament when hot assuming an average temperature coefficient of resistivity α=0.0045(C)−1.
A certain lightbulb has a tungsten filament with a resistance of 19.0 Ω when at 20.0°C and 140 Ω when hot. Assume the resistivity of tungsten varies linearly with temperature even over the large temperature range involved here. Find the temperature of the hot filament.
Resistance in metals increases with increasing temperature according to the equation, ρ(T) = ρo(1 + α(T - To)) where α is the temperature coefficient of resistivity and ρo is the resistivity at temperature To. For a particular wire α = 1.5 × 10-3 1/°C and the resistivity is ρo = 8.5 × 10-7 Ω⋅m at To = 125 °C.
The temperature coefficient of resistance α in equation R(T)=R0[1+α(T−T0)] equals the temperature coefficient of resistivity α in equation ρ(T)=ρ0[1+α(T−T0)] only if the coefficient of thermal expansion is small. A cylindrical column of mercury is in a vertical glass tube. At 20 ∘C, the length of the mercury column is 12.0 cm. The diameter of the mercury column is 1.6 mm and doesn't change with temperature because glass has a small coefficient of thermal expansion. The coefficient of volume expansion of...
A small bulb is rated at 7.50 W when operated at 125 V. The tungsten filament has a temperature coefficient of resistivity alpha = 4.50 times 10^-3/C degree. When the filament is hot and glowing, its temperature is seven times room temperature (20 C degree). What is the resistance of the filament (in ohms) at room temperature?
1. The filament of a standard 100-W light bulb has a resistance of about 100 ohms. For this laboratory the glass of the light bulb is unfrosted, so that the filament can be viewed directly. The light bulb is connected to a variable AC voltage source (a Variac), which can deliver up to 140 volts AC. When the voltage is low, about 20 volts, the filament is a dull, red color. When the voltage is high, 100 V, how does...
Copper wire has a resistivity ρ = 1.7 × 10-8 Ω⋅m when at 20°C and it has a temperature coefficient α = 3.9 × 10-3 K-1. A solid cylinder of copper of length L = 85 cm and diameter D = 2.5 mm has one end held at T1 = 7°C and the other end is held at T2 = 210°C. The temperature increases linearly between the two ends of the cylinder. Given that T= T1 + ( x/L )...