ac current lags the voltage by 90 degree

ac current leads the voltage by 90 degree

ac current and voltage are exactly in phase

ac current is converted to dc voltage

Practice Electronic Principles Multiple Choice Questions Quiz-4

Q.1

If the base supply voltage increases, the Q point moves

down
up
nowhere
off the load line
None of the above

Q.2

Positive ions are atoms that have

Gained an electron
Gained a proton
Lost a proton
Lost an electron
None of the above

Q.3

Which one of the following is a statement of Kirchhoffs current law?

The current through a resistance is proportional to the value of resistance and the IR drop across it
The total current in a parallel circuit is less than the value of the smallest current
The algebraic sum of currents in a loop is equal to zero
The algebraic sum of currents entering and leaving a point is equal to zero
None of the above

Q.4

For a pure capacitor:

ac current and voltage are exactly in phase
ac current leads the voltage by 90 degree
ac current is converted to dc voltage
ac current lags the voltage by 90 degree
None of the above

Q.5

A device that converts chemical energy to electrical energy is called a:

solar cell
thermocouple
chemical cell
electric device
None of the above

Q.6

Which one of the following statements is true?

inductive reactance decreases with operating frequency
inductive reactance is at a maximum for dc source voltages
inductive reactance increases with operating frequency
There is no meaningful relationship between inductive reactance and operating frequency
None of the above

Q.7

A zener diode has a voltage of 10 V and a current of 20 mA. What is the power dissipation?

200 mW
300 mW
20 mW
10 mW
None of the above

Q.8

The component that forms the electrical connection between the rotating coil of wire in a motor and the external source of electrical energy is called the:

rotor
armature
battery
commutator
None of the above

Q.9

In a pure inductor:

ac current leads the voltage by 90 degree
ac current and voltage are exactly in phase
ac current lags the voltage by 90 degree
ac current is converted to dc voltage
None of the above

Q.10

Suppose the peak value of a sinusoidal voltage is 50 V. What is the rms value?

37.4 V
35.4 V
38.74 V
30.4 V
None of the above

Q.11

What is the difference between a conductor and an insulator?

A conductor allows current to flow much easier than an insulator does
An insulator has an excessive number of free electrons, while a conductor has a few free electrons or none at all
An insulator allows current to flow much easier than a conductor does
The difference between conductors and insulators depends on how they are used
None of the above

Q.12

In an intrinsic semiconductor, the number of free electrons

Equals the number of holes
Is less than the number of holes
Is greater than the number of holes
Impossible to say
None of the above

Q.13

Waveforms are graphs that show:

frequency on the vertical axis and amplitude on the horizontal axis
amplitude on the vertical axis and frequency on the horizontal axis
amplitude on the vertical axis and the passage of time on the horizontal axis
the passage of time on the vertical axis and amplitude on the horizontal axis
None of the above

Q.14

When the collector current increases, what does the current gain do?

decreases
stays the same
increases
any of the above
None of the above

Q.15

A circuit has two different voltage sources that are connected in a series-aiding form. If the sources are rated at 6 V and 9 V, what is the total source voltage?

15 V
16 V
7.5 V
8 V
None of the above

Q.16

At room temperature an intrinsic semiconductor has

a few free electrons and holes
many holes
many free electrons
No holes
None of the above

Q.17

A device that converts mechanical into electrical energy is?

solar cell
thermocouple
chemical cell
generator
None of the above

Q.18

Which one of the following kinds of materials has the lowest permeability?

A diamagnetic material
A paramagnetic material
A feiTomagnetic material
All of the above
None of the above

Q.19

The total capacitance of a series capacitor circuit is:

equal to the sun of the individual capacitive-reactance values
equal to the sum of the individual capacitance values
equal to the source voltage divided by total current
less than the value of the smallest capacitor
None of the above

Q.20

If a load resistance is 1 kW, a stiff voltage source has a resistance of

At least 10 Ohm
less than 10 Ohm
More than 100 k Ohm
Less than 100 k Ohm
None of the above

Q.21

When operating above its resonant frequency, a parallel RLC circuit has the characteristics of a:

parallel RL circuit
parallel RC circuit
parallel RLC circuit operated above its resonant frequency
purely resistive circuit
None of the above

Q.22

The total impedance of a parallel RLC circuit:

always increases as the applied frequency increases
is equal to the sum of the values of resistance, inductive reactance and capacitive reactance
always decreases as the applied frequency increases
is maximum at the resonant frequency
None of the above

Q.23

The rise time of a pulse waveform is the time required for the voltage to rise:

from zero to its rms value
from zero to its peak value
from 10% of the peak value to 70.7% of the peak value
from 10% of the peak value to 90% of the peak value
None of the above

Q.24

Assuming 100% efficiency, what is the power being applied to the primary winding of the transformer described in the above question?

200 W
1000 W
20 W
100 W
None of the above

Q.25

To get the Thevenin voltage, you have to

Short the load resistor
Open the load resister
Short the voltage source
Open the voltage source
None of the above

Q.26

A typical light switch in your home is a:

knife switch
toggle switch
rotary switch
momentary push button switch
None of the above

Q.27

Doubling the operating frequency of an inductive circuit:

has no effect on the inductive reactance
doubles the amount of inductive reactance
multiplies the inductive reactance by 6.28
cuts the inductive reactance in half
None of the above

Q.28

A circuit has a Norton current of 10 mA and a Norton resistance of 10 kW. What is the Thevenin circuit?

1000 V and a series resistance of 10 k Ohm
100 V and a parallel resistance of 10 k Ohm
100 V and a series resistance of 10 k Ohm
1000 V and a parallel resistance of 10 kOhm
None of the above

Q.29

Which one of the following properties of a magnetic circuit can be directly compared to resistance in an electrical circuit?

Reluctance
Permeability
Permeance
Retentivity
There is no valid comparison

Q.30

How many types of flow are there in a semiconductor?

0
1
2
4
None of the above