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Which of the following methods can be used to charge a metal sphere positively without touching it . Select the best
This can be possible by induction, if a negative charge rod is placed near the sphere (at a distance not in touch) than it attracts positive charge inside the sphere towards its side and the negative charges collected on other side and when the surface of sphere connected to earth than the negative charge goes to earth and the sphere remain positively charged.
When a negatively charged conductor is connected to earth,
After earthing a positively charged conductor electrons flow from earth to conductor and if a negatively charged conductor is earthed then electrons flows from conductor to earth.
A point charge of 2.0 μC is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?
Two identical conductors of copper and aluminium are placed in an identical electric field. The magnitude of induced charge in the aluminium will be:
As aluminium and copper are metals, their mobile electrons move under the influence of the external field until they reach the surface of the metal and collect there. External electric fields induce surface changes on metal objects that exactly cancel the field within. Since the field applied is same in both case, the induced charge will be the same. Hence, the magnitude of induced charge in the aluminium will be the same as that of copper.
A point charge causes an electric flux of −1.0×103Nm2/C to pass through a spherical Gaussian surface of 10.0 cm radius centred on the charge.
(a) If the radius of the Gaussian surface were doubled, how much flux would pass through the surface?
(b) What is the value of the point charge?
Electric flux, Φ = −1.0 × 103 N m2/C
Radius of the Gaussian surface,
r = 10.0 cm
Electric flux piercing out through a surface depends on the net charge enclosed inside a body. It does not depend on the size of the body. If the radius of the Gaussian surface is doubled, then the flux passing through the surface remains the same i.e., −103 N m2/C.
Electric flux is given by the relation,
q = Net charge enclosed by the spherical surface
∈0 = Permittivity of free space = 8.854 × 10−12 N−1 C2 m−2
= −1.0 × 103 × 8.854 × 10−12
= −8.854 × 10−9 C
= −8.854 nC
Therefore, the value of the point charge is −8.854 nC.
Electric charge, the basic property of matter carried by some elementary particles, such as atoms; ions; electrons; etc, that govern how the particles are affected by an electric or magnetic field.
Electric charge, which can be positive or negative, occurs in discrete natural units and is neither created nor destroyed.
An electric dipole is
An electric dipole is a separation of positive and negative charges. The simplest example of this is a pair of electric charges of equal magnitude but opposite sign, separated by some (usually small) distance. A permanent electric dipole is called an electret.
A hollow spherical conductor of radius 2m carries a charge of 500 μ C. Then electric field strength at its surface is
For forming an electric dipole between two point charges separated by a small distance, the two point charges are of
An electric dipole is tagged as a pair of objects which possess equal & opposite charges, parted by a significantly small distance.
The amount of work done in moving a charge from one point to another along an equipotential line or surface charge is
Since Potential difference between two points in equipotential surfaces is zero , the work done between two points in equipotential surface is also zero .
An electric field can deflect
Only alpha rays are moving with small velocity and having charge so they will be affected by electric field.
Under the influence of the coulomb field of charge +Q, a charge −q is moving around it in an elliptical orbit. Find out the correct statement(s).
Since the charge –q is moving in elliptical orbit so to make its motion stable the total angular momentum of the charge is constant since it experience a centripetal force from the charge +Q so it follow the motion as the motion of earth around sun.
Conservation of charges in tribo electric charging
The triboelectric effect (also known as triboelectric charging) is a type of contact electrification in which certain materials become electrically charged after they come into frictional contact with a different material.
Example: Rubbing glass with fur, or a plastic comb through the hair.
When we charge something with static electricity, no electrons are made or destroyed. Electrons are just moved from one place to another. The net electric charge stays the same. This is called the principle of conservation of charge.
i.e. If a glass rod is rubbed with silk, some electrons moves from glass rod to silk no new charge is generated or destroyed.
Consider a neutral conducting sphere. A positive point charge is placed outside the sphere. The net charge on the sphere is then,
If a charge q is placed outside than the electric field lines incident on the conducting sphere , if some charge is developed due to thee lines than opposite surface becomes oppositely charge and the total charge becomes zero.
Two positive charges
Acc to coulomb's law unlike charges always attract each other while like charges always repel each other.
Ionization of a neutral atom is the
It is not possible to remove or add protons/neutrons to an atom, but electrons can be added or removed by an atom easily.
By adding electrons it becomes negatively charged.
By removing electrons it becomes positively charged.
A charge q is placed at the center of the line joining two equal charges Q. The system of the three charges will be in equilibrium if q is equal to
The situation is as shown in the figure.
Let two equal charges Q each placed at points A and B at a distance r apart. C is the centre of AB where charge q is placed.
For equilibrium, net force on charge Q= 0
The electrostatic force is:
The electrostatic force is an attractive and repulsive force between particles are caused due to their electric charges. The electric force between stationary charged bodies is conventionally known as the electrostatic force.
Two charges A = -2.50 μC and B = 6.0 μC are at a distance of 1 meter from each other. Distance from A at which the electric field is zero in meters is
x = distance of the null point from the small charge
d = distance between two charges
q2 = bigger charge
q1 = small charge
+1 for like charges and -1 for unlike charges
Conductors are materials
Conductors are materials that permit electrons to flow freely from particle to particle. An object made of a conducting material will permit a charge to be transferred across the entire surface of the object.