A common flashlight bulb is rated at 0.34 A and 2.3 V (the values of the current and voltage under operating conditions). If the resistance of the bulb filament at room temperature (20°C) is 1.0 Q, what is the temperature of the filament when the bulb is or 10-316-16.

A tungsten wire in a vacuum has length 26.0 cm and radius 6.00 mm. A potential difference is applied across it. (a) What is the resistance of the wire at 293 K? Ω (b) Suppose the wire reaches an equilibrium temperature such that it emits 70.0 W in the form of radiation. Neglecting absorption of any radiation from its environment, what is the temperature of the wire? (Note: e = 0.320 for tungsten.) K (c) What is the resistance of the wire at the temperature found in part (b)? Assume the temperature changes linearly over this temperature range. Ω. (d) What voltage drop is required across the wire? (e) Why are tungsten lightbulbs energetically inefficient as light sources?

A water heater coil made of Nichrome wire of conductivity o=6.7×10 2-'m¯ dissipates a power of 800 W when connected to a direct current power supply of 120 V. The wire has a cross-sectional area of 16.0x10-/ m². Find the length (in m) of the wire.

The resistance of a wire increases by 22 percent when the temperature of the wire is increased from 10 degrees C to 105 degrees C. What is the temperature coefficent (a) of the wire's material?

A metallic wire is stretched from original length of 1 m to 5 m. If the original cross- sectional area is 2 square millimeters and original resistance is 8 ohms, determine the new resistance (in ohms) of the metallic wire. Assume the volume of the wire is preserved.

If R is the total resistance of three resistors, connected in parallel, with resistances R₁, R₂, R3, then 1/2 = 1/₂+1/2+1/3 R R₁ If the resistances are measured in ohms as R₁ = 64, R₂ = 82, and R3 = 42, with a possible error of 0.5% in each case, estimate the maximum error in the calculated value of R. (Round your answer to three decimal places.) .005 x 22

(a) What is the cost of heating a hot tub containing 1510 kg of water from 10.0°C to 40.0°C, assuming 75.0% efficiency to take heat loss to surroundings into account? The cost of electricity is 9.00¢/(kW • h) and the specific heat for water is 4184 J/(kg · °C). $ (b) What current was used by the 220 V AC electric heater, if this took 4.95 h? Additional Materials O Reading

(a) What is the cost of heating a hot tub containing 1500 kg of water from 10.0ºC to 40.0ºC , assuming 75.0% efficiency to account for heat transfer to the surroundings? The cost of electricity is 9 cents/kW ⋅ h . (b) What current was used by the 220-V AC electric heater, if this took 4.00 h?

When initially at 20°C, the power being supplied to a 691 Ohm resistor in a circuit is 8.29 W. Over time, the temperature of the resistor increase to 168°C. If the temperature coefficient of resistivity of the material composing the resistor is 5.75 x 10-3 °C-1, what power is supplied to the resistor at its operating temperature?

(a) In the figure what value must R have if the current in the circuit is to be 1.3 mA? Take ₁ = 2.7 V, 8₂-5.3 V, and r₁ r2 = 3.9 Q. (b) What is the rate at which thermal energy appears in R? www.i R (a) Number (b) Number ww MI -48₂ i N Units Units <