There is a voltage across an open switch, such as in Figure 21.43. Why, then, is the power dissipated by the open switch small.
The power dissipated is small because the current is very small.
The term "circuit" refers to a set of electrical connections.
Circuits are closed-loop or route systems that consist of a network of electrical components through which electrons can travel.
Resistance of the switch when closed
Resistance of switch when open
Emf of the battery is
The internal resistance of the battery is
External resistance connected in series with the battery is
Current in the circuit when the switch is closed
Current in the circuit when the switch is open role="math" localid="1655897485259"
When the switch is open,
Equivalent resistance in series of the circuit given,
Using Ohm's law, the current in the circuit is given as,
Therefore, when the circuit is open, there is no current in the circuit.
The power dissipated is given as,
Substituting the values in the above expression, we get,
Hence, the power dissipated across the switch when the open comes out to be .
A flashing lamp in a Christmas earring is based on an RC discharge of a capacitor through its resistance. The effective duration of the flash is 0.250 s , during which it produces an average 0.500 W from an average 3.00 V (a) What energy does it dissipate? (b) How much charge moves through the lamp? (c) Find the capacitance. (d) What is the resistance of the lamp?
94% of StudySmarter users get better grades.Sign up for free