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3 years ago

Explain what it means when we say a substance is magnetic

1 answer:

5 0

A magnetic field is a force field, invisibly pushing electrically charged objects just as a gravitational field pulls objects with mass. Whereas all objects with mass exert a gravitational field, however, not all objects have a magnetic field. Magnetic fields are created by electrical charges. Thanks to their structure at the atomic level, some substances -- like the iron in magnets -- have a permanent magnetic field.

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Why is a rotting apple a reaction in which energy is neither absorbed nor released?

o-na [289]

Answer:

Hey

It would have to be C because no net energy is lost.

7 0

2 years ago

What is the driving force for (a) heat transfer, (b) electric current, and (c) fluid flow?

lara31 [8.8K]

Answer:

The driving force for (a) heat transfer is temperature difference. (b) electric current is voltage difference. (c) fluid flow is pressure or hydraulic head difference.

Explanation: (a) The driving force for heat transfer is temperature difference. Heat transfer between two mediums is possible only if the two mediums are at different temperature, the higher the temperature, the higher the heat transfer.

(b) The driving force for electric current is voltage difference. Voltage difference is defined as the potential difference in charge between two points in electrical field. For electric current to occur,the voltage must be high.

(c) The driving force for fluid flow is pressure difference or hydraulic head difference. For fluid to move upward,it requires energy.

3 0

3 years ago

Nonrenewable resources are natural resources that are limited in supply and cannot be replaced as quickly as they are used up.

zysi [14]

Answer:

True

Explanation:

Nonrenewable resources ARE limited in supply. They don't get replaced at the speed they get made. For example: we pump crude oil from the ground at a rate that makes it impossible for crude oil to be replaced. Crude oil takes millions of years to produce

8 0

3 years ago

An emf is induced in a conducting loop of wire 1.22 m long as its shape is changed from square to circular. Find the average mag

Afina-wow [57]

Answer:

The induced emf in the loop is $7.35\times 10^{-4}\ V$

Explanation:

Given that,

Length of the wire, L = 1.22 m

It changes its shape is changed from square to circular. Then the side of square be its circumference, 4a = L

4a = 1.22

a = 0.305 m

Area of square, $A=a^2=(0.305)^2=0.0930\ m^2$

Circumference of the loop,

$C=2\pi r=L\\\\r=\dfrac{L}{2\pi}\\\\r=\dfrac{1.22}{2\pi}=0.194\ m$

Area of circle,

$A'=\pi r^2\\A'=\pi (0.194)^2\\\\A'=0.118\ m^2$

The induced emf is given by :

$\epsilon=\dfrac{\d\phi}{dt}\\\\\epsilon=\dfrac{\d(BA)}{dt}\\\\\epsilon=B\dfrac{A'-A}{t}\\\\\epsilon=0.125 \times \dfrac{0.118-0.0930}{4.25}\\\\\epsilon=7.35\times 10^{-4}\ V$

So, the induced emf in the loop is $7.35\times 10^{-4}\ V$

8 0

3 years ago

Water vapor enters the atmosphere through

Blizzard [7]

Answer:

Heat from the Sun causes water to evaporate from the surface of lakes and oceans. This turns the liquid water into water vapor in the atmosphere. Plants, too, help water get into the atmosphere through a process called transpiration! ... Water can also get into the atmosphere from snow and ice.

Most water vapor enters the atmosphere via evaporation and transpiration. Evaporation occurs when a single water molecule on a liquid water surface gains enough kinetic energy (often by solar radiation) to break the bond which holds the molecules together. Really Hopes this helps!

Explanation:

6 0

2 years ago