Watt, Volt, Current, Capacitor, Diode, Resister, & Circuit
1. What is a watt?
a) A unit of energy
b) A unit of power
c) A unit of force
d) A unit of voltage
2.
Which
of the following equations represents the relationship between power (P),
voltage (V), and current (I) in an electrical circuit?
a) P = V/I
b) P = V + I
c) P = V × I
d) P = V - I
3.
If
a device consumes 500 joules of energy in 10 seconds, what is its power
consumption in watts?
a) 50 W
b) 5 W
c) 5000 W
d) 500 W
4.
A
light bulb is rated at 60 watts. What does this rating indicate?
a) The brightness of the bulb
b) The energy it consumes in one hour
c) The voltage it requires
d) The power it dissipates while
operating
5.
A
motor does 1000 joules of work in 5 seconds. What is its power output in watts?
a) 200 W
b) 5000 W
c) 100 W
d) 20 W
6.
What
is the SI unit of power?
a) Joule
b) Watt
c) Newton
d) Ohm
7.
A
light bulb consumes 60 watts of power. How much energy does it consume in 5
hours?
a) 300 J
b) 360 J
c) 300 W
d) 3600 W
8.
A
machine does 200 joules of work in 4 seconds. What is its power output in
watts?
a) 800 W
b) 50 W
c) 204 W
d) 800 J
9.
If
an electric motor produces 500 joules of work in 10 seconds, what is its power
in watts?
a) 5 W
b) 50 W
c) 5000 W
d) 50,000 W
10.
A
car engine delivers 150 horsepower. What is its power output in watts? (1
horsepower = 746 watts)
a) 111,900 W
b) 150 W
c) 746 W
d) 111,900,000 W
11.
A
device requires 2.5 kilowatts of power to operate. How many watts is this
equivalent to?
a) 250 W
b) 2,500 W
c) 25,000 W
d) 250,000 W
12.
An
electric heater consumes 800 watts of power. How much energy does it consume in
3 hours?
a) 2400 J
b) 2400 W
c) 2400 kWh
d) 2.4 MWh
13.
What
is voltage?
a) The flow of electric charge
b) The resistance of a circuit
c) The potential difference
between two points
d) The rate of electron motion
14.
Which
unit is used to measure voltage?
a) Ampere (A)
b) Watt (W)
c) Joule (J)
d) Volt (V)
15.
If
a circuit has a voltage of 12 volts and a current of 3 amperes, what is the
resistance of the circuit?
a) 4 ohms
b) 9 ohms
c) 15 ohms
d) 36 ohms
16.
In
a series circuit, how does voltage behave?
a) Voltage remains constant across all
components
b) Voltage is divided among
components
c) Voltage increases with each component
d) Voltage decreases with each component
17.
What
is Ohm's Law?
a) V = IR
b) P = VI
c) Q = CV
d) F = ma
18.
If
the voltage across a resistor is 24 volts and the current passing through it is
2 amperes, what is the resistance of the resistor?
a) 12 ohms
b) 48 ohms
c) 26 ohms
d) 14 ohms
19.
What
happens to the voltage in a parallel circuit?
a) Voltage is divided among components
b) Voltage remains constant
across all components
c) Voltage increases with each component
d) Voltage decreases with each component
20.
A
battery has a voltage of 9 volts. If two identical light bulbs are connected in
series to the battery, what is the voltage across each bulb?
a) 3 volts
b) 4.5 volts
c) 6 volts
d) 9 volts
21.
What
is the voltage across an open circuit?
a) Zero volts
b) Positive volts
c) Negative volts
d) Variable volts
22.
If
the voltage in a closed circuit increases, what happens to the current?
a) Current decreases
b) Current increases
c) Current remains unchanged
d) Current becomes negative
23.
What
is the primary characteristic of direct current (DC)?
a) It constantly changes direction.
b) It flows in one direction
only.
c) It has high frequency oscillations.
d) It is unaffected by resistance.
24.
Which
of the following devices is commonly used to generate direct current?
a) Transformer
b) Inductor
c) Rectifier
d) Oscillator
25.
In
a circuit, the voltage of a direct current source is 12 volts. What does this
value represent?
a) The rate of flow of electrons.
b) The amount of charge stored.
c) The energy stored in the circuit.
d) The electric potential
difference between two points.
26.
What
is the SI unit of electric current?
a) Volt
b) Ampere
c) Ohm
d) Watt
27.
A
direct current of 5 A flows through a resistor with a resistance of 10 ohms.
What is the voltage across the resistor?
a) 0.5 V
b) 5 V
c) 10 V
d) 15 V
28.
Which
of the following materials would be a good conductor of direct current?
a) Rubber
b) Glass
c) Copper
d) Plastic
29.
In
a circuit with multiple resistors in series, how does the current passing
through each resistor compare?
a) The current is the same
through each resistor.
b) The current decreases with each
resistor.
c) The current increases with each
resistor.
d) The current varies randomly through each
resistor.
30.
What
is the purpose of a diode in an electrical circuit?
a) To store electric charge.
b) To regulate voltage.
c) To change AC to DC.
d) To allow current to flow in
one direction only.
31.
What
is the direction of conventional current flow in a circuit?
a) From positive to negative
b) From negative to positive
c) It depends on the type of circuit.
d) It changes direction constantly.
32.
Which
of the following statements is true about direct current and alternating current?
a) Direct current is safer to use.
b) Alternating current flows in one
direction only.
c) Direct current changes
direction periodically.
d) Alternating current can be easily stored
in batteries.
33.
What
is the primary difference between direct current (DC) and alternating current
(AC)?
a) DC flows in one direction,
while AC periodically reverses its direction.
b) DC is used for high-voltage
applications, while AC is used for low-voltage applications.
c) DC is safer for human use, while AC is
more efficient for power transmission.
d) DC is generated by batteries, while AC
is generated by power plants.
34.
The
frequency of an AC circuit refers to:
a) The voltage level of the circuit.
b) The rate at which the current
changes direction.
c) The resistance of the circuit.
d) The number of electrons in the circuit.
35.
Which
component is commonly used to measure the magnitude of AC voltage?
a) Voltmeter
b) Ammeter
c) Ohmmeter
d) Multimeter
36.
In
an AC circuit, the peak voltage is 220V. What is the RMS voltage?
a) 220V
b) 154V
c) 311V
d) 110V
37.
Which
of the following devices is used to change the magnitude of AC voltage?
a) Capacitor
b) Diode
c) Transformer
d) Resistor
38.
A
circuit has a resistance of 50 ohms and an inductance of 0.1 H. If the AC
frequency is increased, what happens to the impedance?
a) Impedance increases.
b) Impedance decreases.
c) Impedance remains constant.
d) Impedance becomes zero.
39.
What
is the phase difference between the voltage and current in a purely resistive
AC circuit?
a) 0 degrees
b) 45 degrees
c) 90 degrees
d) 180 degrees
40.
Which
type of AC circuit element stores energy temporarily in its electric or
magnetic field?
a) Resistor
b) Capacitor
c) Inductor
d) Diode
41.
What
is the standard frequency of AC power used in most countries?
a) 50 Hz
b) 60 Hz
c) 25 Hz
d) 75 Hz
42.
Which
phenomenon causes AC signals to be attenuated as they travel through a
conductor?
a) Reflection
b) Refraction
c) Dispersion
d) Skin effect
43.
What
is a capacitor in physics?
a) A device that stores magnetic energy
b) A device that stores gravitational
potential energy
c) A device that stores
electrical energy
d) A device that converts mechanical energy
into electrical energy
44.
Which
of the following factors does NOT affect the capacitance of a parallel plate
capacitor?
a) Area of the plates
b) Distance between the plates
c) Type of dielectric material between the
plates
d) Voltage across the plates
45.
The
unit of capacitance is:
a) Ohms (Ω)
b) Farads (F)
c) Volts (V)
d) Coulombs (C)
46.
In
a parallel plate capacitor, if the distance between the plates is doubled while
the plate area remains the same, how does the capacitance change?
a) Capacitance becomes half
b) Capacitance doubles
c) Capacitance remains the same
d) Capacitance quadruples
47.
If
a dielectric material with a high relative permittivity (κ) is inserted between
the plates of a capacitor, what happens to the capacitance?
a) Capacitance increases
b) Capacitance decreases
c) Capacitance remains the same
d) Capacitance becomes zero
48.
When
a capacitor is connected to a battery, what gets stored in the capacitor?
a) Protons
b) Electrons
c) Ions
d) Electric charges
49.
What
is the time constant (Ï„) of an RC circuit?
a) The time it takes for the
capacitor to fully discharge
b) The time it takes for the capacitor to
fully charge
c) The time it takes for the resistor to
heat up
d) The time it takes for the circuit to
break
50.
When
does the charging of a capacitor in an RC circuit approximately reach 63.2% of
its maximum value?
a) After one time constant (Ï„)
b) After two time constants (2Ï„)
c) After three time constants (3Ï„)
d) After four time constants (4Ï„)
51.
What
happens to the energy stored in a capacitor when the voltage across it is
doubled?
a) Energy becomes half
b) Energy doubles
c) Energy quadruples
d) Energy remains the same
52.
Which
of the following materials is commonly used as a dielectric in capacitors?
a) Copper
b) Aluminum
c)
Glass
d) Iron
53.
What
is the primary function of a diode in an electronic circuit?
a)
Amplification
b)
Signal
modulation
c)
Current rectification
d)
Voltage
regulation
54.
In
which direction does a diode allow current to flow?
a.
Only from anode to cathode
b.
Only
from cathode to anode
c.
Equally
in both directions
d.
It
depends on the voltage applied
55.
What
is the voltage drop typically across a silicon diode when it is forward-biased?
a)
0
volts
b)
0.3
volts
c)
0.7 volts
d)
1.5
volts
56.
When
a diode is reverse-biased, it:
a)
Allows
a large current to flow
b)
Blocks current flow
c)
Acts
as a resistor
d)
Generates
an electromagnetic field
57.
The
region of operation in a diode where a small change in voltage results in a
large change in current is called:
a)
Forward
bias
b)
Reverse
bias
c)
Breakdown region
d)
Avalanche
region
58.
What
is the purpose of the Schottky diode?
a)
Voltage
regulation
b)
Temperature
sensing
c)
High-frequency rectification
d)
Light
emission
59.
The
Zener diode is commonly used for:
a)
Amplification
of signals
b)
Rectification
of AC signals
c)
Voltage regulation and stabilization
d)
Frequency
modulation
60.
Which
type of diode is designed to emit light when forward-biased?
a)
Zener
diode
b)
Schottky
diode
c)
Photodiode
d)
Light-emitting diode (LED)
61.
In
a practical diode, reverse breakdown occurs when:
a)
The
forward voltage exceeds a certain threshold
b)
The reverse voltage exceeds a certain threshold
c)
The
diode is exposed to high temperatures
d)
The
diode is used for amplification
62.
A
diode is considered an ideal conductor when:
a)
It
is forward-biased
b)
It is reverse-biased
c)
It
has a high reverse voltage
d)
It
is exposed to light
63.
What
is the unit of electrical resistance?
a)
Watts
(W)
b)
Ohms (Ω)
c)
Volts
(V)
d)
Amperes
(A)
64.
Which
of the following materials typically has the highest electrical resistance?
a)
Copper
b)
Silver
c)
Gold
d)
Rubber
65.
Two
resistors with resistances 4Ω and 6Ω are connected in series. What is the total
resistance?
a)
10Ω
b)
2Ω
c)
24Ω
d)
8Ω
66.
When
resistors are connected in parallel, their total resistance is:
a)
The
sum of their resistances
b)
The reciprocal of the sum of their reciprocals
c)
The
average of their resistances
d)
The
difference between their resistances
67.
A
12V battery is connected to a resistor with a resistance of 3Ω. What is the
current passing through the resistor?
a)
4 A
b)
36
A
c)
1/4
A
d)
9
A
68.
Which
of the following statements is true regarding the relationship between voltage
(V), current (I), and resistance (R) in a circuit?
a)
V
= I + R
b)
V = I × R
c)
V
= I / R
d)
V
= R / I
69.
The
power dissipated by a resistor with resistance R carrying current I is given
by:
a)
P
= R / I
b)
P
= I2
c)
P
= V / I
d)
P = I2 × R
70.
Which
of the following factors does not affect the resistance of a conductor?
a)
Length
of the conductor
b)
Cross-sectional
area of the conductor
c)
Temperature
of the conductor
d)
Colour of the conductor
71.
The
resistance of a wire is doubled while keeping its length and cross-sectional
area constant. How does this affect the resistivity of the wire?
a)
Resistivity
is halved
b)
Resistivity
is doubled
c)
Resistivity remains the same
d)
Resistivity
is quadrupled
72.
Superconductors
are materials that have:
a)
Extremely
high resistance
b)
No resistance at very low temperatures
c)
Resistance
that increases with temperature
d)
Resistance
that decreases with temperature
73.
What
is the relationship between voltage (V), current (I), and resistance (R) in an
electrical circuit?
a)
V
= I / R
b)
V
= R / I
c)
I = V / R
d)
R
= V / I
74.
In
a circuit, if the voltage remains constant and the resistance is doubled, how
does the current change?
a)
It
doubles
b)
It becomes half
c)
It
quadruples
d)
It
remains unchanged
75.
What
is the potential difference across a resistor with a current of 2.5 A flowing
through it and a resistance of 10 Ω?
a)
0.4
V
b)
25 V
c)
4
V
d)
7.5
V
76.
In
a series circuit with three resistors, if one resistor has a higher resistance
than the others, what happens to the total resistance of the circuit?
a)
It
remains unchanged
b)
It increases
c)
It
decreases
d)
It
becomes zero
77.
Which
of the following statements about parallel circuits is true?
a)
The total current is divided among the components
b)
The
total resistance is the sum of individual resistances
c)
The
potential difference across each component is different
d)
The
total resistance is inversely proportional to the number of components
78.
What
is the purpose of a fuse in an electric circuit?
a)
To control the current in the circuit
b)
To
increase the voltage of the circuit
c)
To
reduce the resistance of the circuit
d)
To
regulate the frequency of the circuit
79. A circuit contains two resistors, R1 and
R2, connected in series. How does the total resistance (R Total) compare to the
individual resistances?
a)
R_total = R1 + R2
b)
R_total
= R1 x R2
c)
R_total
= R1 / R2
d)
R_total
= √(R12 + R22)
80. What is the unit of electric current?
a)
Volts
b)
Ohms
c)
Amperes
d)
Watts
81. A capacitor is fully charged in a
circuit. If it is disconnected from the circuit and then connected to an
uncharged capacitor in parallel, what happens to the charge and voltage?
a)
Charge
and voltage double
b)
Charge
and voltage halve
c)
Charge adds up, but voltage remains the same
d)
Charge
remains the same, but voltage doubles
82. What is the main property of an inductor
in a circuit?
a)
It resists changes in current
b)
It
stores electrical energy
c)
It
regulates voltage
d)
It
acts as a one-way valve for current
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