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2 years ago

Please help me with this question

Engineering

1 answer:

kap26 [50]2 years ago

3 0

Answer:

The current through each lamp is 0.273 Amperes

Power dissipated in each lamp is 0.082W

Explanation:

Battery v = 1.5 V

Each lamp has resistance, r = 1.1 Ohms

The 5 lamps in series will therefore have total resistance, R = 5 * 1.1 = 5.5 Ohms

The current through each lamp, I = v/R = 1.5 / 5.5 = 0.273 Amperes

Power dissipated in each lamp = I² * r = 0.273² * 1.1 = 0.082W

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Zepler [3.9K]

Answer:

Tech A

Explanation:

The amount of energy required to apply the same force with a 1:1 ratio is divided into 4, so you can apply 4 times as much force than a 1:1 ratio. efficiency and speed come into play here, but assuming the machine powering the gear can run at a unlimited RPM, 4:1 will have more force and a slower output speed than a 2:1 ratio.

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An electrical heater is a form of sensible heating process, and heats 0.1m/s of air from 15°C and 80% RH to 50°C? The barometric

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Answer:

The heater load =35 KJ/kg

Explanation:

Given that

At initial condition

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Now from chart

At temperature= 15°C and RH=80%

$h_1=38 \frac{KJ}{kg},v=0.8 \frac{m^3}{kg}$

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2 years ago

A 800-MW steam power plant, which is cooled by a nearby river, has a thermal efficiency of 40 percent. Determine the rate of hea

Arturiano [62]

Answer:

Rate of heat transfer to river=1200MW

So the actual amount of heat rejected ti the river will be less as there will some heat loss to surrounding and in pipes

Explanation:

In order to find the actual heat transfer rate is lower or higher than its value we will first find the rate of heat transfer to power plant:

$Efficiency=\frac{work}{heat transfer to power plant}$

$Heat transfer=\frac{work}{Efficiency\\} \\\\Heat transfer=\frac{800}{0.40}\\\\Heat transfer=2000MW$

From First law of thermodynamics:

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3 years ago

A heat engine that rejects waste heat to a sink at 520 R has a thermal efficiency of 35 percent and a second- law efficiency of

xeze [42]

Answer:

The source temperature is 1248 R.

Explanation:

Second law efficiency of the engine is the ratio of actual efficiency to the maximum possible efficiency that is reversible efficiency.

Given:

Temperature of the heat sink is 520 R.

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Actual thermal efficiency is 35%.

Calculation:

Step1

Reversible efficiency is calculated as follows:

$\eta_{II}=\frac{\eta_{a}}{\eta_{rev}}$

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Step2

Source temperature is calculated as follows:

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$0.5834=1-\frac{520}{T}$

T = 1248 R.

The heat engine is shown below:

Thus, the source temperature is 1248 R.

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2 years ago

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Answer:

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2 years ago

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