Available Answers

1. 1.

   State true or false for each statement and rewrite the false statement correctly.

   1. The number of electrons and protons in an atom are not the same.
   2. If the charge is not in motion, we call it static electricity.
   3. Human body is an insulator of electricity.
   4. When an ebonite rod is rubbed with fur, the electrons move from ebonite to fur.
   5. When, glass rod is rubbed with dry silk cloth, the electrons move from glass to silk.
   6. The cap of gold leaf electroscope is made of copper.
   7. If a glass rod rubbed with silk is brought near the cap of a negatively charged electroscope, the divergence of leaves will decrease.
   8. In induction, a positively charged body can make an uncharged body positively charged.
   9. A lightning conductor saves the building from lightning.
   10. A comb rubbed with dry hair and brought near pieces of paper attracts them, because both comb and paper get similarly charged.
2. 2.

   Fill in the blanks :

   1. In an atom. the number of electrons is equal to the number of __________________.
   2. Two unlike charges __________________ each other.
   3. Two like charges __________________ each other.
   4. When a glass rod is rubbed with dry silk cloth. the glass rod acquires __________________ charge.
   5. __________________ is the surest test for electrification.
   6. __________________ is a non-metal which is a good conductor of electricity.
   7. When a charged rod is touched with the brass cap of gold leaf electroscope, the leaves will __________________.
   8. We may charge an uncharged body by the method of __________________ or __________________.
   9. __________________ protects a building from damage caused by lightning.
   10. A gold leaf electroscope can be negatively charged by conduction by bringing __________________ rod in contact with the brass cap.
3. 3.

   Match the following:

   Two dissimilar charges Two similar charges Silver is a Sulphur is an Ebonite rubbed with fur acquires

   negative charge repel insulator attract conductor

4. 4.

   Tick the most appropriate answer :

   (a) Father of electricity is considered to be

   1. Isaac Newton
   2. Galileo
   3. Albert Einstein
   4. William Gilbert

   (b) Atom, in general, is electrically

   1. neutral
   2. positive
   3. negative
   4. none of the above

   (c) When a glass rod is rubbed with dry silk cloth, the charge acquired by the silk cloth is

   1. positive
   2. negative
   3. both positive and negative
   4. none of the above

   (d) When an ebonite rod is rubbed with fur, the rod acquires

   1. positive charge
   2. negative charge
   3. no charge
   4. none of the above

   (e) When a negatively charged body is brought closer to another negatively charged body, then they will show

   1. attraction
   2. no effect
   3. repulsion
   4. none of the above

   (f) Silver is a

   1. bad conductor of electricity
   2. good conductor of electricity
   3. insulator
   4. none of the above

   (g) Charging a conductor by bringing another charged conductor close to it is called

   1. induction
   2. conduction
   3. convection
   4. radiation

   (h) The factor responsible for charging a conductor is

   1. transfer of protons
   2. transfer of neutrons
   3. transfer of electrons
   4. transfer of both protons and electrons

   (i) An atom with deficiency of electrons is

   1. positive ion
   2. negative ion
   3. neutral
   4. none of the above

   (j) If the charges are not allowed to flow, then it is called

   1. static electricity
   2. magnetism
   3. current electricity
   4. alternating current.
5. 5.

   Who discovered the method of producing electricity by friction?

6. 6.

   Name two substances which can be charged by friction.