Tag: electric charges and fields

Questions Related to electric charges and fields

State whether true or false :

Rain water is a non-conductor of electricity.

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. True

  2. False

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Correct Option: B
Explanation:

False.

Rain water is a conductor of electricity due to The most common one is carbon dioxide. Carbon dioxide itself in not an electrolyte, but it reacts with water to make what is often called "carbonic acid". Carbonic acid is actually a fictitious acid, since there are no molecules of ${H} _{2}{CO} _{3}$ in aqueous solution. But what is present that makes rain water a conductor are $H^+$ and $HCO^{3-}$ ions. 

$CO _2$(aq) $+$ $H _2O$(l) <==> $H^+$ $+$ $HCO^{3-}$ 

$1000$ years ago, that would have pretty much been it. But today we have lots more pollutants in the air that contribute to acid rain and to the conductivity of rainwater. $SO _3$ dissolves in water to make $H _2SO _4$, which exists as $H^+$ and $HSO^{4-}$ ions. $N _2O _5$ dissolves in water to make $HNO _3$, which exists in water as $H^+$ and $NO^{3-}$. These are but a few of the substances that can produce the ions in solution that will make rainwater a conductor.

Which of the following is best insulator?

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. carbon

  2. paper

  3. ebonite

  4. graphite

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Correct Option: C
Explanation:

Out of the given options, ebonite is best insulator. Whereas, carbon and graphite are fair conductors and ebonite is a better insulator than paper.

State whether true or false.
Ebonite is a good conductor of electricity.

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. True

  2. False

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Correct Option: B
Explanation:

Given statement is that "ebonite is a good conductor of electricity". This statement is false. This is because ebonite is a poor conductor of electricity, it is an insulator. Electrons cannot move easily within it, and also it has no free electrons present for conductivity.

Ordinary tap water conducts electric current due to :

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. the dissolved salts in it

  2. higher purity of the water

  3. the bacteria present in it

  4. none of these

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Correct Option: A
Explanation:

Tap water conducts electricity since there are small amounts of calcium and magnesium salts dissolve in it, pure water (distilled or de-ionised) has nothing at all in it that can conduct electricity. This is because water itself isn't a conductor. However, when one dissolves ionic compound such as salts, the ions becomes loosely bound to each other which makes tap water a good conductor of electricity. 

An example in which light emitting diodes are used is :

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. calculator

  2. hard drive

  3. optical drive

  4. analog watch

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Correct Option: A
Explanation:

Light emitting diodes are used in calculators.


Option A is  correct.

Most solid materials are classified as insulators why?

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. They offer large resistance to the flow of electric current

  2. They doesnt do anything

  3. They offer large force to other particles

  4. None

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Correct Option: A
Explanation:

Most solid materials are classified as insulators because they offer large resistance to the flow of electric current. because they do not have free electrons.


Option A is correct.

From below which of them are used in electrostatic experiments and demonstrations?

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. Conductors

  2. Insulators

  3. Semi Conductors

  4. None

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Correct Option: B
Explanation:

Insulators are the materials that do not allow free flow of electrons from atom to atom and molecule to molecule. Subsequently charge is seldom distributed evenly across the surface of an insulator while, insulators are not used for transferring a charge, they do serve a critical role in electrostatic experiments and demonstrations.

Lightning wants to get to ground. It will follow the path(s) of                 to do so.

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. most impedance

  2. least impedance

  3. least distance

  4. least inductance

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Correct Option: B
Explanation:

Lightening gets to the ground if the charges flow from lightening to the ground. It happens when these charges follow a path of least impedance. 

During discharging of a charged glass rod via earthing, the connecting material can be

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. another glass rod

  2. a conducting wire

  3. fur

  4. an ebonite rod

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Correct Option: B
Explanation:

During discharging of a charged glass rod via earthing the connecting material should be such that it allows charge to flow through them easily. Such a material is a conductor. So, the connecting material can be a conducting wire. 

A charged glass rod will get discharged on

physics electric charges and fields conductors and insulators introduction to electrostatics electricity

  1. connecting it to the earth

  2. connecting it to another glass rod

  3. breaking the ends of the rod

  4. Any of the above

Show answer
Correct Option: A
Explanation:

A charged glass rod can be discharged by connecting it to the ground (i.e, earthing it) via a conducting wire. In this way, charge from glass rod will flow to the ground via the conducting wire.