What is not needed for a charge to flow through a conducting wire?

a. an electrical insulator

b. a wire connected in a complete loop

c. a source of electrical energy

The correct answer is an electrical insulator.

Explanation:

Insulator : It is a material which resists the flow of electrons. It has high resistance in comparison to the conductor.

Conductor: It is a material which allows the flow of electrons. It has low resistance in comparison to the conductor.

Battery is a source of electrical energy. It forces the electrons to flow. The rate of flow of electrons constitutes the current.

In the given problem, an electrical insulator is not needed for a charge to flow through a conducting wire.

To design the circuit and to make a current flow in the circuit, a battery, a wire connected in a complete loop and a source of electrical energy are needed.

Therefore, the correct option is (C).

the temperature and the pressure affect solubility. temperature affects by changing the properties of the solvent. the increase in pressure increases solubility, the decrease in pressure decreases solubility.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.