The Soil resistance depends on

A.  Induction motors.

B.  Resistive loads.

C. Synchronous Motors.

D. All of the above.

Answer: D. All of the above

Explanation: 

The resistance of earth is the resistance between the earth and earth electrode. It depends on three factors.

• The resistance of earth electrode
• The contact resistance between electrode surface and soil
• The resistivity of soil between the electrode and earth

The resistivity of soil depends upon

• The electrical conductivity offered by a soil mainly due to electrolysis i.e., the resistivity of a soil is mainly electrolytic in nature
• So, concentration of water, salt (NaCl) and other chemical components in the soil largely determines its resistivity
• The chemical composition of the soil
• The temperature of the soil
• Moisture: moist soil is best suited for earthing purpose
• It is normal practice to insert an earth electrode well below the ground level, to get a stable moist soil in depth
• Earth resistance depends on the depth of the earth electrode, moisture, temperature but it does not depend on operating time.