Sample Problems on Electric Current in Conductors

Question 1: Assume a horizontal plate and positive charge of 50C flows in 5 seconds through that plate. Find the magnitude of the electric current passing through that plate. 

Answer: 

It is known that electric current is the rate of charge passing through the conductor. 

Net charge passing through the conductor q_net = 50C 

Time taken, t = 5 

⇒ 

⇒ I = 10 A 

Question 2: Assume a horizontal plate and positive charge of 20C flows in 2.5 seconds through that plate. Find the magnitude of the electric current passing through that plate. 

Answer: 

It is known that electric current is the rate of charge passing through the conductor. 

Net charge passing through the conductor q_net = 20C 

Time taken, t = 2.5

⇒ 

⇒ I = 8 A 

Question 3: The charge present inside the conductor at a given time is given by the function q(t) below. 

q(t) = sin(t) 

Find the current flowing through the conductor at time t. 

Answer: 

In this case, the rate of charge through the conductor is changing. So, average current cannot be calculated, for such case instantaneous current is calculated. 

⇒ 

⇒ I = cos(t) A 

Question 4: The charge present inside the conductor at a given time is given by the function q(t) below. 

q(t) = t² + 2t

Find the current flowing through the conductor at time t = 2. 

Answer: 

In this case, the rate of charge through the conductor is changing. So, average current cannot be calculated, for such case instantaneous current is calculated. 

⇒ 

⇒ 

⇒ I = 2t + 2

at t = 2. 

I = 2(2) + 2 

⇒ I = 4 + 2 

⇒ I = 6 A

Question 5: The charge present inside the conductor at a given time is given by the function q(t) below. 

q(t) = t + 2t³ + e^t

Find the current flowing through the conductor at time t = 1. 

Answer: 

In this case, the rate of charge through the conductor is changing. So, average current cannot be calculated, for such case instantaneous current is calculated. 

⇒ 

⇒ )

⇒ I = 1 + 6t² + e^t

at t = 1. 

I = 1 + 6t² + e^t

⇒ I = 1 + 6(1) + e 

⇒ I  = 7 + e 

⇒ I = 9.7A

Electric current in conductors is the movement of electric charge through a substance, usually a metallic wire or other conductor. Electric current is the rate at which an electric charge flows past a certain point in a conductor, and it is measured in amperes.

When a potential difference (voltage) is supplied across the ends of a conductor, it induces an electric field within the material. This electric field exerts force on the free electrons in the conductor, causing them to migrate. In this article, we will learn in detail about the electric current in conductors.