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poizon [28]
3 years ago
12

A laptop can convert 400J of electrical energy into a 240J of light and sound. What is the efficiency? Where does the rest of th

e energy go?
Physics
1 answer:
Blababa [14]3 years ago
8 0
Efficiency = (Wanted) energy out ÷ energy in × 100

Energy in = 400J
Wanted Energy out = 240J

Energy cannot be used up, only transferred, so the remaining energy is most likely to be transferred into unwanted energy (loss of energy) such as heat energy.

Efficiency = 240 ÷ 400 × 100
Efficiency = 0.6 × 100
Efficiency = 60%
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Explanation:

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3 years ago
An electric heater is rated at 1400 W, a toaster is rated at 1150 W, and an electric grill is rated at 1560 W. The three applian
gayaneshka [121]

Answer:

The current in the heater is 12.5 A

Explanation:

It is given that,

Power of electric heater, P₁ = 1400 W

Power of toaster, P₂ = 1150 W

Power of electric grill, P₃ = 1560 W

All three appliances are connected in parallel across a 112 V emf source. We need to find the current in the heater. We know that in parallel combination of resistors the current flowing in every branch of resistor divides while the voltage is same.

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I_1=\dfrac{P_1}{V}

I_1=\dfrac{1400\ W}{112\ V}

I_1=12.5\ A

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4 years ago
Which of the following is not found in dry air?
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C.water vapor i hope i helped

5 0
3 years ago
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7nadin3 [17]
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3 years ago
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The pulley system below uses a gasoline engine to raise a drill head up through a smooth drill pipe. The engine provides a const
polet [3.4K]

NB: The diagram of the pulley system is not shown but the information provided is sufficient to answer the question

Answer:

Power = 2702.56 W

Explanation:

Let the power consumed be P

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height, h = 5 m

E = 80 * 9.8 * 5

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Power = \frac{Energy}{time}

To calculate the time, t

From F = ma

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a = 900/80

a = 11.25 m/s²

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The drill head starts from rest, u = 0 m/s

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6 0
3 years ago
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