Question

A 580-mm long tungsten wire, with a 0.046-mm-diameter circular cross section, is wrapped around in the shape of a coil and used as a filament in an incandescent light bulb. When the light bulb is connected to a battery, a current of 0.526 A is measured through the filament. (Note: tungsten has a resistivity of 4.9 × 10-8 Ω • m.). How many electrons pass through this filament in 5 seconds?

Answer 1

Answer: 1.64 *10^19 electrons

Explanation: In order to the explain this problem we have to consider the following:

The current= charge/time; so

as the electrons move in the tungsten wire we have:

0.526 C/s= N electrons per second* charge of electron=

N electrons/s= 0.526/1.6*10^-19= 3.28 *10^18 electrons/s

Then, during  5 seconds  will pass:

3.28 *10^18 electrons/s*5 5s= 1.64 *10^19 electrons