Dielectric Material | MCQs

Explanation

The dielectric constant of water at around 18°C is approximately 80.

This high value makes water an excellent polar solvent for ionic and polar compounds.

Explanation

The electric field due to a positive charge points away from the charge, i.e., radially outward.

Field lines show the direction a positive test charge would move.

Explanation

Mica is a dielectric material that increases the capacitance when placed between capacitor plates.

It does so by reducing the electric field and allowing the capacitor to store more charge for a given voltage.

Explanation

The presence of a dielectric material between the plates of a capacitor reduces the electric field by a factor called the dielectric constant 𝐾

The electric field E in a capacitor with a dielectric is related to the field E0 without the dielectric by:

E= E0/K

​When the dielectric material is removed, the dielectric constant K becomes 1 (for vacuum or air), and the electric field reverts to its original strength, increasing by a factor of 𝐾

Thus, when the dielectric is removed, the electric field increases.

Explanation

• Charge: Q=1mC=1×10^−3C

• Voltage: $V = 100,text{V}$

• The formula for capacitance is:

C=Q/V​

Calculation:

$$C = frac{1 times 10^{-3}}{100} = 1 times 10^{-5},text{F} = 10,mutext{F}$$