What you mean by potential difference?

Draw a diagram to represent the electric field around a positively charged sphere.

Draw a diagram to represent the electric field between two horizontal parallel plates. The upper plate has a positive charge and the lower plate has a negative charge.

Electric ray fish are a group of  flattened cartilaginous fishes with enlarged pectoral fins. They are known for being capable of producing an electric discharge, ranging from $8$ to $220$ volts, depending on species, and they use this electric discharge to stun prey and for defence.

Fill in the blank by choosing from the brackets.

_____ (dry cell/ alkaline cell) is one example of primary cells.

Inverters and generators are _____ giving devices.

(Choose from the following: electricity/ magnetic energy)

(magnetism,$4.5 \mathrm{V}$,$3.0 \mathrm{V}$, gravitational attraction, potential difference, potential, higher, lower, $0 \mathrm{V}$) 

Water in the waterfall flows from a higher level to the lower level because of _____.