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

Which of the following is an electrical insulator :

  1. Aluminium

  2. Gold

  3. Rubber

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Metals are generally good conductors of electricity. So, Gold and Aluminium are good conductors of electricity. 
Non-metals are poor conductors of electricity.
So rubber, being a non-metal, is an electrical insulator and hence a poor conductor of electricity.

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

Bulb does not glow when the probs are hanged in air. The reason is:

  1. air absorbs the electricity

  2. air is a bad conductor of electricity

  3. electricity is discharged into air

  4. air disperses the electricity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For bulb to glow there should be current passing through it's entire circuit. But when probs are hanged in the air the circuit breaks as air do not conduct electricity (or bad conductor of electricity). 

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

Metals are good conductors because

  1. Outer electrons are strongly bound to the atom.

  2. Outer electrons are loosely bound to the atom.

  3. Inner electrons are loosely bound to the atoms.

  4. Protons can detach from the nucleus and conduct electricity.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Metals have loosely bound outer electrons that is they have charge carriers which can move easily (current) when a potential difference is applied. Therefore, these loosely bound outer electrons make metals good conductors. 

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

Why is electrical wiring usually made from copper and not silver?

  1. Copper is a better conductor

  2. Copper is a better insulator

  3. Copper is less expensive

  4. Copper is non magnetic
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Silver is a better conductor, non magnetic but expensive material compared to copper therefore copper is generally used for electrical wiring.

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

An electrolyte is :

  1. a cell

  2. a metal

  3. a liquid that conducts electricity

  4. sugar
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Answer is C.
An Electrolyte is a substance that dissociates into ions in solution and acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium, and phosphate are examples of electrolytes, informally known as lytes. 
Therefore, it a liquid that conducts electricity.
Multiple choice physics electric charges and fields conductors and insulators introduction to electrostatics electricity

Some materials have electrons that are tightly bound to the nucleus and are not free to travel within the substance. These materials are called .............

  1. conductors

  2. insulators

  3. semiconductors

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Some materials have electrons that are tightly bound to the nucleus and are not free to travel within the substance. These materials are called insulators.
An electrical insulator is a material whose internal electric charges do not flow freely, and therefore make it very hard to conduct an electric current under the influence of an electric field.