电荷守恒
电荷是物质的一种物理性质,因此它在存在电场的情况下会受到力。这些电荷为静电学领域和电气工程等大学科奠定了基础。当电流通过它们时,电荷会流过我们的电线。它允许电力存在于我们的现实生活中。电荷有正有负,既不能被破坏,也不能被创造。它只能从一个身体转移到另一个身体。这就是电荷守恒定律背后的思想。让我们详细看看这些概念。
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这个世界上所有的物质都是由原子和分子组成的。在一般情况下,所有这些原子和分子都是电中性的,所有电荷都是平衡的。要使中性体带电,需要去除其中一种电荷。带电体总是意味着电子不足或电子过剩。假设电子携带负电荷。因此,物体可以通过从原子中去除一些电子而带正电。同样,同一个物体可以通过获得一些电子而带负电。
在现实生活中,每当一个身体与另一个身体摩擦时。其中一个物体失去电子,另一个获得电子,从而带电。电流由于电荷的流动而流动。有些物质允许电流通过它们,而另一些则不允许。这些物质被归类为导体或绝缘体。
Conductors: Conductors are those substances which allow the passage of electricity through them. They have electric charges(electrons) which are relatively free to move around the body of the conductor.
Example – Metals, Human and Animal bodies.
Insulators: Insulators are those substances which do not allow the passage of electricity through them. They also have electric charges(electrons) but they are not free to move around in the body. Thus, this body cannot conduct electricity.
Example – wood, rubber, clothes etc.
电荷守恒
众所周知,当物体相互摩擦时,会发生电子交换,从而在物体中产生电荷。请注意,在这个过程中,电荷从一个物体转移到另一个物体,但没有产生或破坏电荷。孤立系统是与系统外的任何人都没有联系的系统。在这样的系统中,电荷只能通过带电粒子从一个物体转移到另一个物体来产生。这就是电荷守恒定律背后的思想。
For an isolated system, the total charge inside the system is always conserved.
不可能在孤立系统内产生或破坏净电荷。虽然电荷可以通过一些自然过程产生,但它始终保持电荷守恒定律。例如,在自然界中,有时在放射性过程中,会产生电荷。例如,
中子自身解离产生质子和电子。在这种现象中,产生了电荷,但系统的净电荷保持不变。
假设有一个多体系统,现在这样的系统可以处于两种状态:
- 所有的身体都是中性的,每个人的电荷都是平衡的。在这种情况下,默认保持电荷守恒定律。
- 有些物体带正电,有些物体带负电。这表明电荷已经从一个物体转移到另一个物体。但是由于这些粒子没有与系统外的任何东西接触。净电荷保持不变。电子只是在物体之间重新分配以产生电荷。
电荷的可加性
电荷可分为正电荷和负电荷。这些费用可以代数相加。电荷只有大小和性质,没有方向。这些符号在对费用进行加减运算时使用。例如,假设一个系统有两个带有电荷 q 1和 q 2的物体。设总电荷为 q,
q = q 1 + q 2
To generalize the above rule, let’s say there are n-charges in a system q1, q2, ,…..qn. The total charge on the system is given by,
Q = q1 + q2 + …. qn
电荷量化
如上所述,身体上的电荷是由于电子交换而产生的。这意味着,任何带电体的电荷必须是最小电荷单位“e”的倍数。 “e”被认为是电子上的电荷,其值为,
e = 1.6 x 10 -19库仑或 C。
所以,一般来说,物体上的任何电荷“q”是,
q = ne
让我们看一些示例问题
示例问题
问题 1:说明以下陈述是对还是错:
- 木头是电的良导体。
- 在导体中,电子不能自由移动。
- 一个物体可以有相当于 0.5e 的电荷。
- 对于任何系统,总电荷是守恒的。
回答:
1. False,
Wood is an insulator; it cannot conduct electricity.
2. False,
In a conductor, there are some electrons which can move around freely inside it. For this reason, it is able to transfer the charge and conduct electricity.
3. False.
No, the smallest unit of the charge is “e”, which is the charge held by an electron. When bodies are charged, they transfer electrons. For developing a charge of 0.5e, that means only half of the electron should be transferred. There is no technique to split an electron into two parts.
4. False,
The statement is a little misleading, charge is conserved but for only those systems which are isolated.
问题2:下图中给出的系统由多个主体组成。这些机构持有一些指控。电荷为q 1和q 2 ,电荷值分别为+5C和-2C。找出系统上的净费用。
解决方案:
There is a mixture of positive and negative charges. From the earlier mentioned properties, charges can be added and subtracted algebraically.
In this case,
Positive Charges
q1 = 5C
Negative Charges
q2 = -2C
If there are n-charges in a system q1, q2, …..qn. The total charge on the system is given by,
Q = q1 + q2 + …. qn
Q = q1 + q2
⇒Q = (5 -2) C
⇒Q = 3C
问题3:下图中给出的系统由多个主体组成。这些机构持有一些指控。电荷为q 1 、q 2 、q 3和q 4 ,电荷值分别为+5C、+10C、-2C、-15C。找出系统上的净费用。
解决方案:
There is a mixture of positive and negative charges. From the earlier mentioned properties, charges can be added and subtracted algebraically.
In this case,
Positive Charges
q1 = 5C, q2 = 10C
Negative Charges
q3 = -2C, q4 = -15C
If there are n-charges in a system q1, q2, …..qn. The total charge on the system is given by,
Q = q1 + q2 + …. qn
Q = q1 + q2 + q3 + q4
⇒Q = 5 + 10 -2 – 15
⇒Q = 15 – 17
⇒Q = -2C
问题4:当物体上有1C电荷时转移了多少电子。
回答:
One property of charge is, it is always quantized
Q = ne
In this case,
Q = 1 and e = e = 1.6 x 10-19 Coulombs or C.
The goal is to find “n”.
Q = ne
⇒1 = n(1.6 x 10-19)
⇒ 6.24 × 1018 = n
So, 6.24 × 1018 electrons are transferred.
问题5:当物体上有-10C电荷时转移了多少电子。
回答:
One property of charge is, it is always quantized
Q = ne
In this case,
Q = -10 and e = e = 1.6 x 10-19 Coulombs or C.
The goal is to find “n”.
Q = ne
⇒-10 = n(1.6 x 10-19)
⇒
⇒ 6.24 × 1019 = n
So, 6.24 × 1019 electrons are transferred.
问题 5:找出一摩尔水中的负电荷。
回答:
One mole of water contains 6.02 × 1023 molecules of H20.
Number of electrons in H2O = 2(Number of electrons in H) + Number of electrons in O
⇒Number of electrons in H2O = 2(1) + 8
⇒Number of Electrons in H2O = 10
Total number of electrons in one mole of water = 6.02 × 1023 × 10
= 6.02 × 1024
One property of charge is, it is always quantized
Q = ne
In this case,
n = 6.02 × 1024 and e = e = 1.6 x 10-19 Coulombs or C.
The goal is to find “n”.
Q = ne
⇒Q = (6.02 × 1024)(1.6 x 10-19)
⇒Q = 9.632 × 105C