首页
登录
职称英语
Atoms, the basic building blocks of matter, are made of three basic components:
Atoms, the basic building blocks of matter, are made of three basic components:
游客
2024-02-19
5
管理
问题
Atoms, the basic building blocks of matter, are made of three basic components: protons, neutrons and electrons. The protons and neutrons cluster together to form the nucleus, the central part of the atom, and the electrons orbit about the nucleus. Protons and electrons both carry an electrical charge(电荷). The charges they carry are opposite to each other; protons carry a positive electrical charge while electrons carry a negative electrical charge. Neutrons carry no charge at all.
Electricity is the movement of charged particles, usually electrons, from one place to another. Materials that electricity can move through easily are called conductors. Most metals, such as iron, copper and aluminum, are good conductors of electricity. Other materials, such as rubber, wood and glass, block the flow of electricity. Materials which prevent the flow of electricity are called insulators (绝缘体). Electrical cords are usually made with both conductors and insulators. Electricity flows through a conductor in the center of the cord. A layer of insulation surrounds the conductor and prevents the electricity from "leaking" out.
Objects usually have equal numbers of positive and negative charges, but it isn’t too hard to temporarily create an imbalance. One way scientists can create an imbalance is with a machine called a Van de Graaff generator. It creates a large static charge by placing electrons on a metal dome(钟形罩) using a motor and a big rubber band. Since like charges repel, the electrons push away from each other as they collect on the dome. Eventually, too many electrons are placed on the dome and they leap off, creating a spark that looks like a bolt of lightning. Have you ever received a shock after having walked across a carpet? This shock was caused by extra electrons you collected while walking across the carpet. Your body became like the dome of the Van de Graaff generator, full of extra electrons looking for a way to get away. The path back to the carpet was blocked by the shoes you were wearing, but they were able to move through your hand and into the object that you touched, causing the shock. So, the next time you walk across a carpet and shock your friend on the ear, tell them you were just trying to be a Van de Graaff generator!
选项
A、The charges of protons equal the charges of electrons.
B、The charges of neutrons equal the sum of the charges of electrons and protons.
C、The charges of protons equal the sum of the charges of electrons and neutrons.
D、The charges of electrons equal the sum of the charges of protons and neutrons.
答案
B
解析
本题问“根据本文下列哪一个对原予内情况的说法是正确的?”文章第一段第三、四、五句介绍原子内的电荷组成,“质子和电子都带电荷。但它们所带电荷正好相反,质子带正电荷,电子带负电荷,而中子不带电”,即质子和电子的电荷数相加为零,等于中子电荷数,故[B]“中子的带电荷数等于质子和电子电荷之和”正确。[A]“质子的带电荷敷等于电子带电荷敷”。质子与电子所带电荷相反,所以不能相等。[C]“质子的带电荷敷等于电子和中子电荷之和”。质子与电子所带电荷相反,中子带电为零,所以不能相等。[D]“电子的带电荷敷等于质于和中子电荷之和”。电子与质子所带电荷相反,中子带电为零,所以不能相等。
转载请注明原文地址:https://tihaiku.com/zcyy/3465453.html
相关试题推荐
I’vealreadytoldyouthatI’mgoingtobuyit,_____________(无论花多少钱).nomatter
Theprimeministerinsistedthat____________(成立委员会)tolookintothematter.ac
Tasteissuchasubjectivematterthatwedon’tusuallyconductpreference
Tasteissuchasubjectivematterthatwedon’tusuallyconductpreference
Tasteissuchasubjectivematterthatwedon’tusuallyconductpreference
[originaltext]Fewbuildingsonearthcancompetewiththelegendarybeauty
[originaltext]Fewbuildingsonearthcancompetewiththelegendarybeauty
[originaltext]W:Simon,couldyoureturnthetoolsIlendyouforbuildingthe
[originaltext]W:Simon,couldyoureturnthetoolsIlendyouforbuildingthe
[originaltext]W:Simon,couldyoureturnthetoolsIlendyouforbuildingthe
随机试题
Dohalfofallmarriagesreallyendindivorce?It’sprobablythemostoften
LittledidIknow______(多少经验能够使我获益).howmuchexperiencewouldbenefitme①所译部分作宾语
年终清理
采用超声对测法检测基桩完整性,收发换能器以相同步长由下向上移动,其步长不应大于(
患者55岁,绝经2年,腰背部疼痛,足跟痛,急躁易怒,五心烦热,心烦少寐,腰膝酸软
下列关于法人成立条件的表述,正确的有( )。 A.法人成立的条件就是法人的设
使人格各部分整合和统一起来的核心力量是()。 A.自我意识B.自我认知C
人参、黄芪的共同功效是A.大补元气 B.补气开阳 C.补气固表 D.补气利
当分部工程较大或较复杂时,可按()将分部工程划分为若干子分部工程。A.材料种类
与砂砾石地基相比,软土地基具有的特点有()。A.承载能力差 B.空隙率大
最新回复
(
0
)