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3 years ago

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The operating temperature of a tungsten filament in an incandescent light bulb is 2450 K, and its emissivity is 0.350. Find the

surface area of the filament of a 150 W bulb if all the electrical energy consumed by the bulb is radiated by the filament as electromagnetic waves. (Only a fraction of the radiation ap- pears as visible light.)

1 answer:

laila [671]3 years ago

8 0

Answer:

A = 2.1 × 10^(-4) m²

Explanation:

We are given;

Temperature; T = 2450 K

Emissivity; ε = 0.35

Bulb rating; H = 150 W

To calculate the surface area, we will use the formula;

H = AεσT⁴

Where σ is stephan boltzman constant with a value of 5.66 × 10^(−8) W/m²⋅K⁴

Making A the subject of the formula, we have;

A = H/εσT⁴

Plugging in the relevant values gives;

A = 150/(0.35 × 5.66 × 10^(−8) × 2450⁴)

A = 2.1 × 10^(-4) m²

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2 years ago

Help it’s multiple choice 11 through 15 please!

riadik2000 [5.3K]

1. • Here, force of gravity on the block = 20 N.

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• The coefficient

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• Force of friction =

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3. It is option b. force that is required to give a one kilogram object the acceleration of 1 m/s^2.

Newton is the SI unit of force. As mentioned earlier, force = mass × acceleration. The SI unit of mass and acceleration is Kg and m/s^2 respectively.

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So, the mass of object B is greater than that of object A.

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Hope you could get an idea from here.

Doubt clarification - use comment section.

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2 years ago

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beks73 [17]

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Replacing our values

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4 years ago

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Vadim26 [7]

<h2>The voltmeter reading will be 35.7 volt </h2>

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5 0

3 years ago