19 ohm resistor, and across the parallel resistors
14 Calculate the length of a constantin wire of
diameter 0.6 mm and resistivity 1.1 x 10-6
Sem required to construct a standard resistor of
resistance 35 92.
(SCIGCE)
15 A battery of three cells in series, each of e. m.f.
2 V and internal resistance 0.5 N is connected
to a 2 12 resistor in series with a parallel
combination of two 3 12 resistors. Draw the
circuit diagram and calculate:
the effective external resistance
b. the current in the circuit
the lost volts in the battery
d. the current in one of the 3 12 resistors.
(SC/GCE)
of a cell is greater than
a.
C.

Tungsten-filament lightbulb emits light based on the temperature of the filament. which phenomenon does this demonstrate?

In a thunderstorm, charge builds up on the water droplets or ice crystals in a cloud. thus, the charge can be considered to be distributed uniformly throughout the cloud. for the purposes of this problem, take the cloud to be a sphere of diameter 1.00 kilometer. the point of this problem is to estimate the maximum amount of charge that this cloud can contain, assuming that the charge builds up until the electric field at the surface of the cloud reaches the value at which the surrounding air breaks down. this breakdown means that the air becomes highly ionized, enabling it to conduct the charge from the cloud to the ground or another nearby cloud. the ionized air will then emit light due to the recombination of the electrons and atoms to form excited molecules that radiate light. in addition, the large current will heat up the air, resulting in its rapid expansion. these two phenomena account for the appearance of lightning and the sound of thunder. take the breakdown electric field of air to be eb=3.00ă—106n/c. part a estimate the total charge q on the cloud when the breakdown of the surrounding air is reached. express your answer numerically, to three significant figures, using ďµ0=8.85ă—10â’12c2/(nâ‹…m2) .

Aperson walks first at a constant speed of 4.89 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.95 m/s. what is the average speed over the entire trip?