Tag: static electricity

Questions Related to static electricity

Can conductors be charged by friction?

physics static electricity exchange of electrons methods used for charging electric charge

  1. Yes

  2. No

  3. It is not possible to charge conductor at all

  4. None of these

Show answer
Correct Option: B
Explanation:

Conductor cant be charged by friction.
They are charged by
$(1)$ Induction
$(2)$ Conduction

State whether the given statement is True or False :
It is possible to charge objects without ever touching the object to be charged to the one used to charge it. 

physics static electricity exchange of electrons methods used for charging electric charge

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

The statement given is that "it is possible to charge objects without ever touching the objects to be charged". This statement is true. This charging process is called charging by induction. It is a process by which a charged body makes a conductor electrically charged without physical contact. The charges on a body by the process of induction are known as induced charges.

Rubber has greater electron affinity than fur. A rubber object is charged by friction with animal fur. The rubber object is than used to charge an object A by the method of contact. Then object A will be charged

physics static electricity exchange of electrons methods used for charging electric charge

  1. positive

  2. negative

  3. neutral

  4. none of these

Show answer
Correct Option: B
Explanation:

The rubber object becomes negatively charged since it would acquire electrons from fur. It would then charge then object A with negative charge since contact charging result in charging an object with same type of charge.

An object A is charged by friction using animal furs. Animal fur has greater electron affinity than object A. What would be charge of object A?

physics static electricity exchange of electrons methods used for charging electric charge

  1. positive

  2. negative

  3. neutral

  4. none of the above

Show answer
Correct Option: A
Explanation:

Due to friction, objects gets charged. The electrons are transferred between two objects. The material with greater electron affinity will receives electrons, and the other will lose electrons. Thus, object will A loses electrons and will acquires positive charge.

Which depicts charging by conduction?

physics static electricity exchange of electrons methods used for charging electric charge

  1. When we to touch an uncharged conductor with a charged conductor, the charged conductor shares the current with uncharged conductor

  2. When we to touch an uncharged conductor with a charged conductor, the charged conductor shares the charge with uncharged conductor

  3. When we to touch an uncharged conductor with a charged conductor, the charged conductor shares the mass with uncharged conductor

  4. None of the above

Show answer
Correct Option: B
Explanation:

When we to touch an uncharged conductor with a charged conductor, the charged conductor shares the charge with uncharged conductor. This is called charging by conduction.

A neutral metal sphere is touched to a negatively charged metal rod. As a result the sphere will be_____ and the metal rod will be ________ . Fill in the gaps

physics static electricity exchange of electrons methods used for charging electric charge

  1. Positively charged

  2. Negatively charged

  3. Neutral

  4. None

Show answer
Correct Option: B
Explanation:

When the neutral metal sphere is touched with the negatively charged metal rod, both of them try to achieve same potential and hence some negative charge flows from rod to sphere for both of them to have negative charges.
Since the total charge is conserved, the sum of the negative charges in them would be equal to the originally present negative charge in the rod.

 Identify how the electrical energy is conducted through a material.

physics static electricity exchange of electrons methods used for charging electric charge

  1. free electrons impacting and transferring energy to each other

  2. the conductivity of the atoms in the material

  3. an energetic electron passing all the way through the material

  4. free electrons dissipating energy through friction

  5. atoms that hold on tightly to their electrons

Show answer
Correct Option: A
Explanation:

Free electrons in a material increases the mobility of flowing electrons into the material. The free electrons impact and transfer energy to each other. It increases the number of electrons that flow when same potential difference is applied.

Two identical conducting balls having positive charges $q _1$ and $q _2$ are separated by a distance r. If they are made to touch each other and then separated to the same distance, the force between them will be

physics static electricity exchange of electrons methods used for charging electric charge

  1. less than before

  2. same as before

  3. more than before

  4. zero

Show answer
Correct Option: C
Explanation:

If they are made to touch each other, the electrostatic conduction will occur. As a result the total charge will get distributed equally on both the balls because both the balls are identical in nature. 


Initially, $F \propto q _1q _2$      (Since $F = \dfrac{kq _1q _2}{r^2}$)


Now after making contact, charge on each ball will become $Q _1=Q _2=\dfrac{q _1+q _2}{2}$
Now, $F' \propto (\dfrac{q _1 + q _2}{2})^2$
(Because they are separated to the same distance) 


From above we can say that $F' > F$

An uncharged insulated conductor A is brought near a charged insulated conductor B. Then for charge and potential of B :

physics static electricity exchange of electrons methods used for charging electric charge

  1. both will remain constant

  2. both will change

  3. the charge will remain constant, but potential will decrease

  4. the charge will remain constant, but potential will increase

Show answer
Correct Option: C
Explanation:

By induction negative charge developes on surface of A close to B and positive charge developes on surface of A away from B, (when B carries positive charge). Therefore, overall potential of B decreases, charge of B remains unchanged.

A positively charged rod is brought near an uncharged conductor. If the rod is suddenly withdrawn, the charge left on the conductor will be :

physics static electricity exchange of electrons methods used for charging electric charge

  1. positive

  2. negative

  3. zero

  4. cannot say

Show answer
Correct Option: C
Explanation:

Positively charged rod induces negative charge on the side of the sphere closer to the rod and an equal positive charge on the side away from the rod. When the rod is withdrawn, the negative charges move to neutralise the equal positive charge. The charge left is zero.