Question

question 32
the source of electrons in an ordinary electrical circuit is
a dry cell, wet cell or battery.
the back emf of motors.
the power station generator.
the electrical conductor itself.
question 33
if you plug an electric toaster rated at 100 v into a 220 v outlet, the current in the toaster will be about
half what it should be
the same as if it were plugged into 110 v.
more than twice what it should be.
twice what it should be

Explanation:

Question 32

In an ordinary electrical circuit, the source of electrons is the electrical conductor itself. Conductors have free electrons that can move when a potential difference is applied. A dry cell, wet cell, or battery provides the potential difference (voltage) to make the electrons move, not the electrons themselves. The back emf of motors is a counter - electromotive force and not a source of electrons. The power station generator provides electrical energy (in the form of voltage) to distant circuits, but the electrons in the local circuit come from the conductor.

According to Ohm's law \(I=\frac{V}{R}\), assuming the resistance \(R\) of the toaster is constant (a reasonable assumption for a simple analysis, neglecting temperature - related resistance changes in the short term). If the rated voltage \(V_{rated}=100V\) and the applied voltage \(V_{applied} = 220V\). Let the current at rated voltage be \(I_{rated}=\frac{V_{rated}}{R}\) and the current at applied voltage be \(I_{applied}=\frac{V_{applied}}{R}\). Then \(\frac{I_{applied}}{I_{rated}}=\frac{V_{applied}}{V_{rated}}=\frac{220}{100}=2.2\)

Answer:

the electrical conductor itself.

Question 33