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Arlecino [84]
3 years ago
15

2. It is a measuring instrument used to record the amount of

Engineering
1 answer:
lyudmila [28]3 years ago
3 0

Answer:

The correct option is;

D. Electric meter

Explanation:

An electric meter is a metering device that is used for the measurement of the electric power consumption of an electrical powered tools, a living space or a building

Electric meter readings are used by electric utility company to sell electric power to consumers at a given rate such that it allows the electric utility company to receive payment for the total power supplied, and for the consumer to regulate the amount of power consumed

The electric meters are usually calibrated in kilowatt hour (kWh) and prepaid meter displays the amount of units of power bought, while post paid meters are usually read once each billing period which is usually one month.

You might be interested in
Chemical materials that are transported are called..
svetlana [45]

Answer:

Transport Molecules

Explanation:

I believe the answer is transport molecules because development of a cell membrane that could allow some materials to pass.

3 0
3 years ago
6.3.3 Marks on an exam in a statistics course are assumed to be normally distributed
bekas [8.4K]

Answer:

- The calculated p-value (0.392452) is higher than the significance level at which the test was performed, hence, the null hypothesis is true and μ = 60

- 95% Confidence interval for the population mean score = (47.4, 84.1)

Explanation:

The sample of 4 students had scores of 52, 63, 64, 84.

First of, we need to compute the sample mean, we do not need the sample standard deviation as the population variance is given as 5

Mean = (Σx)/N

x = each variable

N = number of variables = 4

Mean = (52 + 63 + 64 + 84)/4

Mean = 65.75

Sample Standard deviation = σ

= √[Σ(x - xbar)²/N]

xbar = mean = 65.75

Σ(x - xbar)² = 532.75

σ = √[532.75/4] = 11.54

in hypothesis testing, the first thing is usually to state the null and alternative hypothesis.

From the question, the null hypothesis has already been stated as

H₀: μ = 60

The alternative hypothesis would then be that the population mean score isn't equal to 60

Hₐ: μ ≠ 60

Since the population distribution is normal and the sample standard deviation is to be used, we use the t-test statistic

t = (x - μ₀)/σₓ

x = sample mean = 65.75

μ₀ = Standard to be compared against = 60

σₓ = standard error = (σ/√n) = (11.54/√4) = 5.77

t = (65.75 - 60)/5.77 = 0.9965 = 1.00

checking the tables for the p-value of this t-statistic

Degree of freedom = df = n - 1 = 4 - 1 = 3

Significance level = 0.05 (95% confidence level)

The hypothesis test uses a two-tailed condition because we're testing in two directions.

p-value (for t = 1.00, at 0.05 significance level, df = 3, with a two tailed condition) = 0.392452

The interpretation of p-values is that

When the (p-value > significance level), we fail to reject the null hypothesis and when the (p-value < significance level), we reject the null hypothesis and accept the alternative hypothesis.

So, for this question, significance level = 0.05

p-value = 0.392452

0.392452 > 0.05

Hence,

p-value > significance level

This means that we fail to reject the null hypothesis & say that there is enough evidence to conclude that the populatiom mean score is equal to 60.

b) Confidence Interval for the population mean is basically an interval of range of values where the true population mean can be found with a certain level of confidence.

Mathematically,

Confidence Interval = (Sample mean) ± (Margin of error)

Sample Mean = 65.75

Margin of Error is the width of the confidence interval about the mean.

It is given mathematically as,

Margin of Error = (Critical value) × (standard Error of the mean)

Critical value will be obtained using the t-distribution.

To find the critical value from the t-tables, we first find the degree of freedom and the significance level.

Degree of freedom = df = n - 1 = 4 - 1 = 3

Significance level for 95% confidence interval

(100% - 95%)/2 = 2.5% = 0.025

t (0.025, 3) = 3.18 (from the t-tables)

Standard error of the mean = 5.77

95% Confidence Interval = (Sample mean) ± [(Critical value) × (standard Error of the mean)]

CI = 65.75 ± (3.18 × 5.77)

CI = 65.75 ± 18.3486

95% CI = (47.4014, 84.0986)

95% Confidence interval = (47.4, 84.1)

Hope this Helps!!!

7 0
3 years ago
At a certain location, wind is blowing steadily at 10 m/s. Determine the mechanical energy of air per unit mass and the power ge
ale4655 [162]

Answer:

<em>a) 50 J/kg</em>

<em>b) 721 67 KW</em>

<em></em>

Explanation:

The velocity of the wind v = 10 m/s

diameter of the blades d = 70 m

efficiency of the turbine η = 30%

density of air ρ = 1.25 kg/m^3

The area of the blade A = \pi d^2/4

A = \frac{3.142 * 70^2}{4} = 3848.95 m^2

The mechanical energy air per unit mass is gives as

e = v^2/2 = \frac{10^2}{2} = <em>50 J/kg</em>

<em></em>

Theoretical Power of the turbine P = ρAve

where

ρ is the density of air

A is the area of the blade

v is the velocity of the wind

e is the energy per unit mass

substituting values, we have

P = 1.25 x 3848.95 x 10 x 50 = 2405593.75 W

Actual power = ηP

where η is the efficiency of the turbine

P is the theoretical power of the turbine

Actual power = 0.3 x 2405593.75 = 721678.1 W

==> <em>721 67 KW</em>

7 0
3 years ago
Free ideas free points. You will be reported for answering "no" or I don't know
KengaRu [80]

Answer:

Here are some cool ideas that you could do

-Zero fuel aircraft

-Advanced Space Propulsion Technologies

-Smart Automation and Blockchain

These are some things I've been working on for a few years lol, maybe you will have more luck

5 0
3 years ago
The atmosphere within a room is at 70 °F dry-bulb temperature, 50 percent degree of saturation, and 14.696 psia pressure. The in
Gre4nikov [31]

Answer:

Given that the temperature of the window is below the dew point it will condensate.

Explanation:

A psychrometric chart (like the one attached) will give you the information needed. This chart is for 14.696 psia.

On the bottom horizontal axes you have the dry-bulb temperature, in this case 70°F, going up from this point you can reach the 50% relative humidity curve (red point on chart), going horizontally from this point to the 100% relative humidity you get the dew point temperature (the point at which moisture will condensate) (blue point on chart). In this case the dew point is 50°C. Given that the temperature of the window is below the dew point it will condensate.

6 0
3 years ago
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