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Conceptual questions

Is the object in a conductor or an insulator? Justify your answer.

External field lines entering the object from one end and emerging from another are shown by lines.
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If the electric field lines in the figure above were perpendicular to the object, would it necessarily be a conductor? Explain.

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The discussion of the electric field between two parallel conducting plates, in this module states that edge effects are less important if the plates are close together. What does close mean? That is, is the actual plate separation crucial, or is the ratio of plate separation to plate area crucial?

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Would the self-created electric field at the end of a pointed conductor, such as a lightning rod, remove positive or negative charge from the conductor? Would the same sign charge be removed from a neutral pointed conductor by the application of a similar externally created electric field? (The answers to both questions have implications for charge transfer utilizing points.)

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Why is a golfer with a metal club over her shoulder vulnerable to lightning in an open fairway? Would she be any safer under a tree?

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Can the belt of a Van de Graaff accelerator be a conductor? Explain.

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Are you relatively safe from lightning inside an automobile? Give two reasons.

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Discuss pros and cons of a lightning rod being grounded versus simply being attached to a building.

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Using the symmetry of the arrangement, show that the net Coulomb force on the charge q size 12{q} {} at the center of the square below ( [link] ) is zero if the charges on the four corners are exactly equal.

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Four point charges, one is q a, second is q b, third is q c, and fourth is q d, lie on the corners of a square. q is located at its center.
Four point charges q a size 12{q rSub { size 8{a} } } {} , q b size 12{q rSub { size 8{b} } } {} , q c size 12{q rSub { size 8{c} } } {} , and q d size 12{q rSub { size 8{d} } } {} lie on the corners of a square and q size 12{q} {} is located at its center.

(a) Using the symmetry of the arrangement, show that the electric field at the center of the square in [link] is zero if the charges on the four corners are exactly equal. (b) Show that this is also true for any combination of charges in which q a = q b size 12{q rSub { size 8{a} } =q rSub { size 8{b} } } {} and q b = q c size 12{q rSub { size 8{b} } =q rSub { size 8{c} } } {}

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(a) What is the direction of the total Coulomb force on q size 12{q} {} in [link] if q size 12{q} {} is negative, q a = q c size 12{q rSub { size 8{a} } =q rSub { size 8{c} } } {} and both are negative, and q b = q c size 12{q rSub { size 8{b} } =q rSub { size 8{c} } } {} and both are positive? (b) What is the direction of the electric field at the center of the square in this situation?

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Considering [link] , suppose that q a = q d size 12{q rSub { size 8{a} } =q rSub { size 8{d} } } {} and q b = q c size 12{q rSub { size 8{b} } =q rSub { size 8{c} } } {} . First show that q size 12{q} {} is in static equilibrium. (You may neglect the gravitational force.) Then discuss whether the equilibrium is stable or unstable, noting that this may depend on the signs of the charges and the direction of displacement of q size 12{q} {} from the center of the square.

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If q a = 0 size 12{q rSub { size 8{a} } =0} {} in [link] , under what conditions will there be no net Coulomb force on q size 12{q} {} ?

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In regions of low humidity, one develops a special “grip” when opening car doors, or touching metal door knobs. This involves placing as much of the hand on the device as possible, not just the ends of one's fingers. Discuss the induced charge and explain why this is done.

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Tollbooth stations on roadways and bridges usually have a piece of wire stuck in the pavement before them that will touch a car as it approaches. Why is this done?

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Suppose a woman carries an excess charge. To maintain her charged status can she be standing on ground wearing just any pair of shoes? How would you discharge her? What are the consequences if she simply walks away?

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Questions & Answers

what is mutation
Janga Reply
what is a cell
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how is urine form
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classification of plants, gymnosperm features.
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how many types of solid did we have
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What is Atoms
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urine is formed in the nephron of the renal medulla in the kidney. It starts from filtration, then selective reabsorption and finally secretion
onuoha Reply
State the evolution relation and relevance between endoplasmic reticulum and cytoskeleton as it relates to cell.
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how is urine formed in human
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malaria is caused by an insect called mosquito.
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Malaria is cause by female anopheles mosquito
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Malaria is caused by plasmodium Female anopheles mosquitoe is d carrier
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what are pathogens
Don Reply
In biology, a pathogen (Greek: πάθος pathos "suffering", "passion" and -γενής -genēs "producer of") in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s.[1][2
Zainab
A virus
Commander
Definition of respiration
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respiration is the process in which we breath in oxygen and breath out carbon dioxide
Achor
how are lungs work
Commander
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in the mouth
EZEKIEL
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stimulates the follicle to release the mature ovum into the oviduct
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endocrine secrete hormone and regulate body process
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while pituitary gland is an example of endocrine system and it's found in the Brain
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Biology is the study of living organisms, divided into many specialized field that cover their morphology, physiology,anatomy, behaviour,origin and distribution.
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biology is the study of life.
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Biology is the study of how living organisms live and survive in a specific environment
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Source:  OpenStax, College physics for ap® courses. OpenStax CNX. Nov 04, 2016 Download for free at https://legacy.cnx.org/content/col11844/1.14
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