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Mamont248 [21]
3 years ago
10

A 60 W lightbulb has a resistance of 240 ohms. At the operating temperature of the tungsten filament, the resistivity is approxi

mately5.0x10^-7 ohms. If the wire used to make the filament is 0.040 mm in diameter (a typical value), how long must the filament be
Physics
1 answer:
irakobra [83]3 years ago
6 0

Answer:

L = 6.032 m

Explanation:

The resistance of a wire is given by

      R = ρ L / A

done ρ is the resistivity of matter, L is the length and A is the area

      L = R A /ρ

the area of ​​a circle is

    A = π r² = π d² / 4

    L = R π d² / 4ρ

in the problem they indicate the resistance of 240 Ω, the diameter of 0.040 mm and the resistivity of 5 10⁻⁷ Ω / m

Let's reduce the diameter to SI units

   d = 0.040 mm (1 m / 1000 mm) = 4 10⁻⁵ m

let's calculate

     L = 240 π (4 10⁻⁵) 2 / (4 5 10⁻⁷)

     L = 6.0319 m

     L = 6.032 m

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Answer:

The correct solution will be "12.0 A".

Explanation:

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On substituting the given values, we get

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3 years ago
A hot-water stream at 80 ℃ enters a mixing chamber with a mass flow rate of 0.5 kg/s where it is mixed with a stream of cold wat
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\dot{m_{2}}=0.865 kg/s

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we know

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\dot{m_{1}}h_{1}+\dot{m_{2}}h_{2}=\dot{m_{3}}h_{3}

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3 years ago
a college student produces about 100 kcal of heat per hour on the average what is the rate of energy production and joules
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Given:

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\begin{gathered} Rate=100\ast4.184 \\  \\ \text{Rate}=418.4\text{ KJ/hour} \end{gathered}

Therefore, the rate of energy production in joules is 418.4 kJ/h which is equivalent to 418400 Joules

ANSWER:

418.4 kJ/h

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