Answer :
Presbyopia is a common vision condition associated with aging. It occurs when the eye gradually loses the ability to see things clearly up close. This happens because the lens of the eye becomes less flexible, making it difficult to focus on nearby objects.
Presbyopia is usually corrected with reading glasses, bifocals, or progressive lenses, which help refocus light directly on the retina so that you can see more clearly up close.
Electric current is the flow of electric charge. It is the rate at which charge flows through a surface. In household circuits, this flow is made by the movement of electrons through a conductor, like a copper wire.
The unit of electric current is the ampere (A), which measures the number of electrons (or charge) passing a point in a circuit per second.
Electric potential difference, also known as voltage, is the amount of work needed to move a unit charge from one point to another in an electric field. It is essentially the energy difference that drives the flow of electric current between two points.
The unit of electric potential difference is the volt (V).