In a television tube the picture is formed by streams of electrons hitting the screen. The current is 20 mA. How much electric charge hits the screen in 30 minutes?​

Quantity of charge = 36 Coulombs.

Explanation:

Given the following data;

Current = 20 mA = 20/1000 = 0.02 Amperes

Time, t = 30 minutes to seconds = 30 * 60 = 1800 seconds

To find the quantity of charge;

Quantity of charge = current * time

Quantity of charge = 0.02 * 1800

Quantity of charge = 36 Coulombs.

this is poiselle's equation from fluid mechanic in physics. mech eng