DC Theories pre-exam quiz

Question 1

When checking a diode with an ohmmeter, when the meter leads are connected to the diode, the meter should show a resistance. If the meter leads are reversed, it should show infinity.

True
False

Answer 1

True

Question 2

As the diameter of a wire increases, its resistance will also increase.

True
False

Answer 2

False

Question 3

When calculating the total resistance of a parallel circuit, the result will always be lower than the lowest resistance.
True
False

Answer 3

True

Question 4

In a circuit with two or more resistances in parallel, the total resistance in the circuit is the sum of the resistances in the circuit.

True
False

Answer 4

False

Question 5

Ohmmeters are to be used only on circuits that are de-energized.

True
False

Answer 5

True

Question 6

Which of the following atomic particles is not found in the nucleus of an atom?

Electron.

Neutron.

Proton.

All of the above.

Answer 6

Neutron

Question 7

Which of the following formulas is used to calculate the current flowing through a circuit?

I = E × R.

R = E × I.

I = E ÷ R.

R = E ÷ I.

Answer 7

I = E/R

Question 8

Which substance can be used to shield instruments from magnetic flux?

Glass.

Soft iron.

Copper.

Mica.

Answer 8

soft iron

Question 9

If a parallel circuit has three loads of equal resistance and a voltage of 120 V is applied to the circuit, what will the voltage drop be across each load?

30 V.

40 V.

60 V.

120 V.

Answer 9

120v

Question 10

The amount of energy used to generate a magnetic field is called ____.

Answer 10

magnetomotive force

Question 11

To find the watts of electrical power in an electrical circuit, you multiply ____.

ohms and amperes

ohms and volts

volts and amperes

volts, amperes, and ohms

Answer 11

volts and amperes

Question 12

An element in an electric heating unit is applied to a 232-volt power supply. The current flow through the element is 19 amperes. What is the resistance of the element?

8 ohms

10 ohms

12 ohms

14 ohms

Answer 12

12 ohms

Question 13

What happens to the current in a circuit if the resistance is increased?

The current remains the same.

The current increases.

The current decreases.

This cannot be determined.

Answer 13

the current decreases

Question 14

An ampere is ____.

the difference in potential between two charges

a measure of the quantity of electrons flowing past a point in the electrical circuit in a given time

the unit of measure for resistance

the unit of measure for capacitance

Answer 14

a measure of the quantity of electrons flowing past a point in the electrical circuit in a given time

Question 15

If five electrons combine with three protons, the net charge will be ____.

negative

positive

zero

neutral

Answer 15

negative