Chapter 5

Question 1

What is electric current and conventional current

Answer 1

Conventional current is the direction of positive charge flow, while electric current is the rate of flow of electric charge

Question 2

explain potential difference mathematically

Answer 2

The charge leaving the positive end of a power producing terminal (like a battery) gradually looses potential energy. Thus, there is a difference per coulomb of charge between the two terminals, as part of it is also transferred to the device. This is termed as potential difference.

ΔV = ΔU/q = ΔW/q

(unit is volt/ when a PE of 1 unit is needed to move a charge of 1 coulomb from one point to another)

Question 3

What is emf?

Answer 3

Electromotive force is the energy supplied by a batter per unit positive charge when it flows through a closed circuit. In other words, EMF is the electric force that’s created when energy is converted into electricity.

Positive charge enters the battery at its lower potential point, so work has to be done by the battery to drive the potential higher. Consider this work W done on charge q, then EMF is given by
3 = W/Q

Its SI unit is J/C=V or volt. Examples include solar panels, batteries, or generators.

Question 4

What is Ohm’s Law?

Answer 4

Relationship between the electric flow of the current flowing through a conductor and the potential difference across it.

It states that current flowing through a conductor is directly proportional to the potential difference applied across its ends provided that physical differences like temperature are kept constant.

If V is the PE across two ends of a conductor, then current I will flow through it:
I ∝ V —- I =V/R

R is the proportionality constant and is known as resistance.