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3 years ago

If you run a 500 W computer for 4 hours, your electric meter will read ; this is a measure of ___ "used"

Physics

2 answers:

emmasim [6.3K]3 years ago

7 0

Answer:

If you run a 500 W computer for 4 hours, your electric meter will read 2kWh; this is a measure of energy "used". The correct answer is D.

Explanation: Energy is defined as the capacity of doing work and is occurs in different forms( electrical, kinetic, potential energy). Electrical energy consumption can be calculated or measure through the multiplication of the power( W or kW) used by the number of hours during which the power is consumed. Therefore the unit of energy is kWh. From the question,

500W was used for 4 H

Therefore energy consumed

500× 4= 2000Wh. To convert to kWh

Divide by 1000,

2000÷ 1000= 2.

There energy consumed in kWh is,

2kWh energy.

Katen [24]3 years ago

3 0

Answer:

D) 2 kWh, energy

Explanation:

Energy = power×time

For electricity,

E = Pt.................... Equation 1

Where E = Electric Energy, P = power, t = time.

Given: P = 500 W, t = 4 hours.

Substitute into equation 1

E = 500(4)

E = 2000 Wh

E = (2000/1000) kWh

E = 2 kWh.

Hence the right option is D) 2 kWh, energy

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A metal wire breaks when its tension reaches 100 newton. If the radius and length of the wire were both doubled then it would br

serg [7]

Answer:

200 N

Explanation:

Since Young's modulus for the metal, E = σ/ε where σ = stress = F/A where F = force on metal and A = cross-sectional area, and ε = strain = e/L where e = extension of metal = change in length and L = length of metal wire.

So, E = σ/ε = FL/eA

Now, since at break extension = e.

So making e subject of the formula, we have

e = FL/EA = FL/Eπr² where r = radius of metal wire

Now, when the radius and length are doubled, we have our extension as e' = F'L'/Eπr'² where F' = new force on metal wire, L' = new length = 2L and r' = new radius = 2r

So, e' = F'(2L)/Eπ(2r)²

e' = 2F'L/4Eπr²

e' = F'L/2Eπr²

Since at breakage, both extensions are the same, e = e'

So, FL/Eπr² = F'L/2Eπr²

F = F'/2

F' = 2F

Since F = 100 N,

F' = 2 × 100 N = 200 N

So, If the radius and length of the wire were both doubled then it would break when the tension reached 200 Newtons.

7 0

3 years ago

An electron moves at 0.130 c as shown in the figure (Figure 1). There are points: A, B, C, and D 2.10 μm from the electron.

Olegator [25]

Hi there!

We can use Biot-Savart's Law for a moving particle:
$B= \frac{\mu_0 }{4\pi}\frac{q\vec{v}\times \vec{r}}{r^2 }$

B = Magnetic field strength (T)
v = velocity of electron (0.130c = 3.9 × 10⁷ m/s)

q = charge of particle (1.6 × 10⁻¹⁹ C)

μ₀ = Permeability of free space (4π × 10⁻⁷ Tm/A)

r = distance from particle (2.10 μm)

There is a cross product between the velocity vector and the radius vector (not a quantity, but specifies a direction). We can write this as:

$B= \frac{\mu_0 }{4\pi}\frac{q\vec{v} \vec{r}sin\theta}{r^2 }$

Where 'θ' is the angle between the velocity and radius vectors.

a)
To find the angle between the velocity and radius vector, we find the complementary angle:

θ = 90° - 60° = 30°

Plugging 'θ' into the equation along with our other values:

$B= \frac{\mu_0 }{4\pi}\frac{q\vec{v} \vec{r}sin\theta}{r^2 }\\\\B= \frac{(4\pi *10^{-7})}{4\pi}\frac{(1.6*10^{-19})(3.9*10^{7}) \vec{r}sin(30)}{(2.1*10^{-5})^2 }$

$B = \boxed{7.07 *10^{-10} T}$

b)
Repeat the same process. The angle between the velocity and radius vector is 150°, and its sine value is the same as that of sin(30°). So, the particle's produced field will be the same as that of part A.

In this instance, the radius vector and the velocity vector are perpendicular so

'θ' = 90°.

$B= \frac{(4\pi *10^{-7})}{4\pi}\frac{(1.6*10^{-19})(3.9*10^{7}) \vec{r}sin(90)}{(2.1*10^{-5})^2 } = \boxed{1.415 * 10^{-9}T}$

d)
This point is ALONG the velocity vector, so there is no magnetic field produced at this point.

Aka, the radius and velocity vectors are parallel, and since sin(0) = 0, there is no magnetic field at this point.

$\boxed{B = 0 T}$

3 0

2 years ago

Which value is represented by the slope of the line?

netineya [11]

The slope of the line is

(change in ' y ' between the ends) / (change in ' x ' between the ends)

Slope = (630g - 0) / (70 cm^3 - 0)

Slope = (630 / 70) g/cm^3

<em>Slope = 9.0 g/cm^3</em>

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3 years ago

Which best describes a nonmagnetic material?

Natali [406]

Material that is not attracted to metal

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3 years ago

Read 2 more answers

Explain different types of thermometer and their thermometry substance

Rudiy27

Answer:

Explained below

Explanation:

1) Liquid in glass thermometer: This type of thermometer is used primarily to measure the temperatures from inspection of changes in volume of liquid.

Thermometry substance is mercury or alcohol

2) Gas thermometer: This type is used to measure temperature as a result of changes in gas pressure or volume.

Thermometry substance is Gas.

3) Resistance thermometer: This type is used to measure temperature due to changes in electric resistance.

Thermometry substance is Resistance wire.

4) Thermocouple thermometer: This type is used to measure the temperature due to changes in electrical potential difference occurring between two metal junctions.

Thermometry substance is two wires that are dissimilar.

5) Bimetallic thermometer: This is a type of thermometer that measures temperature by converting temperature into mechanical displacement by making use of Bimetallic strip.

Thermometry substance is two metals that are dissimilar.

3 0

3 years ago

If you run a 500 W computer for 4 hours, your electric meter will read ____; this is a measure of _______ "used"

If you run a 500 W computer for 4 hours, your electric meter will read ; this is a measure of ___ "used"