COMEDK2024PhysicsCurrent Electricity
The drift velocity of free electrons in a conducting wire is the order of 10⁻⁴ ~m / s . Yet, the bulb glows very quickly after the switch is put ON because
Options
- Athe random speed of electrons is very high of order of 10^6 ~m / s
- Bthe electrons transfer their energy very quickly through collisions
- Celectric field is set-up in the wire with a speed of light producing a current through each cross-section, alm
- Dthe random speed of electrons is very low of order of 10⁻⁶ ~m / s
Correct answer
C. electric field is set-up in the wire with a speed of light producing a current through each cross-section, alm
Step-by-step solution
When electric field is applied, the random motion of all free electrons converted into uni-directional within very short duration of time of order 10⁻⁹ ~s . Which in turn sets up on electric field instantaneously. Thus, a current through each cross-section is produced almost instantaneously. Hence, the bulb glows very quickly.