what is the speed of current?

Question

suppose a bulb connected by a wire and the switch is very distance say about 100Km. how many seconds needed to glow after switching ON?

Answer 1

Depends a lot on the type of bulb but assuming an incandescent it would be virtually instantly. Remember from physics that the electron current velocity does not have to be very high at all because what is actually happening is a displacement of electrons throughout the entire length of the wire. It only takes a few extra electrons per linear meter to produce a rapid displacement of electrons throughout the wire

Sorry DW electrons do not travel at C in a wire. That is a bad misconception propagated by incompetent high school physics teachers.

Answer 2

When a metal wire is connected across the two terminals of a DC voltage source such as a battery, the source places an electric field across the conductor. The moment contact is made, the free electrons of the conductor are forced to drift toward the positive terminal under the influence of this field. The free electron is therefore the current carrier in a typical solid conductor. For an electric current of 1 ampere rate, 1 coulomb of electric charge (which consists of about 6.242 × 1018 electrons) drifts every second through the imaginary plane through which the conductor passes.

The current I in amperes can be calculated with the following equation:
I=Q/t
where,


Q=is the electric charge in coulombs (ampere seconds)
t= is the time in seconds

(Electric currents in solid matter are typically very slow flows. For example, in a copper wire of cross-section 0.5 mm², carrying a current of 5 A, the drift velocity of the electrons is of the order of a millimetre per second. To take a different example, in the near-vacuum inside a cathode ray tube, the electrons travel in near-straight lines ("ballistically") at about a tenth of the speed of light.)

Answer 3

Many hours

Doug is right.

Think of this: an electron moves real fast, but it moves in any directions, it keeps crashing against other ones, etc. and changing its directions. After a while it will be have advanced a little bit, but only this. So, the current speed is not the velocity of light

Ana

Answer 4

The electric field within the wire (which is what causes the electrons to move) travels at 300,000,000 m/s. But individual charges (electrons) travel much more slowly at a few cm/s.


Doug

Answer 5

THE SIGNAL travels at Speed of light is C which is measured in m/s

3x10^8 m/s to be exact

if you're 100,000 m away then

100000/3x10^8=3.33x10^-4

Oops and multiply by two for the light to each your eyes:

6.66x10^-4

and as far as resistance and what not. You didn't ask if you meant realistically or theoretically. And to the rest of you, READ THE QUESTION!

Answer 6

electric travells at the speed of light 186ooo miles per second , so if the switch was 10 miles away it would take .000054 seconds

Answer 7

depends on what car it is in at the time