Physics- Charges and Fields.
Charges and fields are fundamental concepts in electromagnetism. Electric charge is a property of particles that causes them to experience a force in an electric field. Charges can be positive or negative, with like charges repelling and opposite charges attracting. An electric field is a region around a charged object where other charges experience a force. The field’s strength and direction depend on the source charge’s magnitude and distance. Magnetic fields, generated by moving charges or magnetic materials, exert forces on other moving charges. Together, electric and magnetic fields are described by Maxwell’s equations, forming the foundation of classical electromagnetism.
If an object is positively charged, theoretically the mass of the object
Decreases slightly by a factor of 9.11*10-31 kg.
If an object is positively charged it loses some of its electrons. The mass of an electron is 9.11*10-31 kg. So, if a positively charged body loses ‘n’ number of electrons, it mass decrease by the amount n*9.11E-31kg.
Why is gold used in the Gold-leaf electroscope?
Gold is malleable.
Though gold is a costly metal it is used in electroscope because of the property malleability. This means very thin and light sheets can be formed from gold simply by hammering or rolling and hence the deflection of the light gold plates increases.
What happens to the plates of the apparatus if we measure alternating charge using a Gold-leaf oscilloscope?
The plates give a proper divergence.
The divergence of the plates of the Gold-leaf oscilloscope depends only on the presence of a charge, not on the quality of charge i.e. positive or negative. So, if the charge changes from positive to negative and vice versa the degree of divergence of the plates remains the same.
The correct diagram of charge distribution in a hollow sphere?
The same charges repel each other. So, they try to maintain maximum distance from each other and hence they try to remain at the outer surface of an object. If the charge remains on the inner surface or throughout the body, they will repel each other with greater force.
Dr. Gilbert tried to hold a brass rod by hand and induce static electricity in it by friction. Why did he fail?
The induced static charge flew through his hand and body to the ground.
The human body is a good conductor and hence the charge produced by friction flew through his body to the ground. We can tackle the problem simply by holding the brass rod with the help of some insulated holder.
Gold-leaf electroscope can be used
To detect the presence of charge as well as its nature (positive or negative).
If the apparatus is initially in contact with some positively charged body and then comes in contact with another charged body and if the divergence increases we can deduce that the second body is also positively charged. If the divergence decreases then the second body must be negatively charged.
When a glass rod is rubbed with silk, what kind of charge will be developed on glass?
According to electrostatic series, glass is situated above silk. So, if the glass is rubbed with silk, the positive charge on glass and negative charge on silk is produced. Similarly, we can predict what is the nature of charge if we rub two di-electric substances together.
1 Coulomb = ________ Electro Static Unit.
3*109.
Number of electrons in 1 Coulomb charge is
6.25*1021.
Electron has the charge of 1.602*10-19 Coulomb. So, the number of electrons in 1 Coulomb of charge is
11.602∗10−19 = 6.25*1021. This huge number of electrons can be accumulated to form 1C of charge. Thus, we can conclude that we need Avogadro’s number of electrons (approximately) to get 100C charges.
Two equally charged spheres attract each other. Now if they touch each other then they will
Don’t attract or repel.
The two spheres are oppositely charged by the same amount. So if they come in contact, both of their charges are neutralized. So they become uncharged and don’t attract or repel each other.