Interaction between like and Unlike Charges

Q. What happens when a positively charged glass rod is made to touch the metal knob of an electroscope?

1. The leaves of the electroscope become negatively charged.
2. The leaves of the electroscope would repel each other.
3. The leaves of the electroscope become positively charged.
4. The leaves of the electroscope would attract each other.

Q.

Where do we use static electricity in everyday life?

Q.

Question 3(a)

State whether the following statement is true or false.
Like charges attract each other.

Q. What will happen if we run two same materials against each other? Will they acquire a charge?Why/Why not?

Q. Raj was able to charge a plastic comb by rubbing his dry hair but not a metal. Why?

Q.

Question 8
Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon?

Q.

Like charges ___ and unlike charges ___ each other.

1. repel, attract

2. attract, attract

3. attract, repel

4. repel, repel

Q. When a glass rod rubbed with silk is brought near a charged plastic straw rubbed with polythene there is an attraction between the two. Identify the charge on the plastic straw.

1. Positive

2. Can't be predicted

3. Neutral

4. Negative

Q.

The force between two charged objects is called the _____ force.

Q. Why did the rubbed steel spoon did not get attracted to the
paper ?

Q. Do we actually touch things?
Does Adam of an object that is the atom of another?

Q.

What is the convention used to define a particular charge acquired as positive and negative? [2 MARKS]

Q.

State whether the following statements are true or false :

(a) Like charges attract each other.

(b) A charged glass rod attracts a charged plastic straw.

(c) Lightning conductor cannot protect a building from lightning.

(d) Earthquakes can be predicted in advance.

(e) An earthquakes of magnitude 2 on Richter Scale is ten times as strong as an earthquake of magnitude 1 on the same Scale.

(f) The plates of earth's crust are continuously moving.

(g) An earthquake is measured and recorded by using an instrument called electrocardiograph.

Q. In an experiment, a charged object attracts another object. What can be understood from this?

1. The attracted object must be oppositely charged

2. The attracted object must be similarly charged

3. The attracted object must be uncharged

4. Can't say

Q.

Plastic straws A and B are rubbed with a dry cotton cloth. What will happen if they are brought near each other?

Q.

When a neutral body conceded to earth is brought closer to a negatively charged body, then

1. it becomes negatively charged.

2. it consists of equal positive and negative charge.

3. it becomes positively charged

4. no change in charge on it.

Q.

Electricity which does not flow is known as.

Q.

What are electrical forces and their characteristics?

Q.

When two charged glass rods, after being rubbed with a silk cloth are brought towards each other, they ___.

1. attract each other

2. repel each other

3. neither attract nor repel

4. cannot be determined

Q.

A PC monitor is usually covered in dust because:

1. The room needs cleaning

2. None of these

3. The dust particles are attracted by static charges on the monitor

4. The dust particles are attracted by magnets in the monitor

Q.

A negatively charged rod is held close to the disc of a neutral gold leaf electroscope. What kind of charge is produced on the
i) disc
ii) gold leaves?

Q.

Match the following:

Column A Column B

(a) Two like charges (i) negative charge

(b) Two unlike charges (ii) repel

(c) Silver is a (iii) insulator

(d) Silk is an (iv) attract

(e) Ebonite rod rubbed with fur acquires (v) conductor

Q.

Explain:

(i) Why a charged balloon is repelled by another charged ball?

(ii) Why an uncharged balloon is attracted by another charged balloon?

Q.

What is the unit of electrostatic force?

Q.

A positively charged object repels another charged object held near it. What is the nature of charge on the other object ?

Q.

A negatively charged object attracts another charged objects placed near it. What is the nature of charge on the other object ?

Q.

Now that we know that the two glass rods become charged when rubbed with a silk cloth, it would be safe to conclude they acquire ___ charges.

Q. Human body is a good conductor of electricity.

1. True
2. False

Q.

Fill in the blanks:

(a) Like charges ___ while unlike charges ___.

(b) Mercury is a ___ of electricity while pure water is ___ of electricity.

(c) An ebonite rod when rubbed with fur acquires the ___ charge.

(d) When an uncharged conductor is brought in contact with the disc of a gold leaf electroscope, it leaves ___.

(e) Charge is shared in charging a conductor by the method of ___.

Q.

Write true or false for each statement:

(a) The number of electrons and protons in an atom are same.

(b) If the charge is not in motion, we call it static electricity.

(c) Human body is a conductor of electricity.

(d) When an ebonite rod is rubbed with fur, the electrons move from ebonite to fur.

(e) When a glass rod is rubbed with the dry silk cloth, the electrons move from glass to silk.

(f) The cap of gold leaf electroscope is made of copper.

(g) If a glass rod rubbed with silk is brought near the cap of a negatively charged electroscope, the divergence of leaves will decrease.

(h) In induction, a positively charged body can make an uncharged body positively charged.

(i) A lighting conductor saves the building from lighting.

(j) When a comb is rubbed with dry hair both comb and paper get similarly charged.

(k) A glass rod rubbed with silk repels an ebonite rod rubbed with fur.

(l) When an ebonite rod is rubbed with fur, the protons move from the ebonite rod to the fur.

(m) A conductor has a large number of free electrons.

(n) An ebonite rod can be charged by touching it with a charged copper rod.

(o) To find whether a body is charged or not, an uncharged electroscope is used.

(p) To find whether the charge on a body is positive or negative, an uncharged electroscope is used.

(q) If a negatively charged rod is brought near a negatively charged pith ball electroscope, the pith ball will be stuck with the rod.