Electronics Practice Questions
SPM (Malaysia) · SPM Physics · 150 free MCQs with instant results and detailed explanations.
150
Total
48
Easy
79
Medium
23
Hard
Start Practicing Electronics
Take a timed quiz or customize your practice session
Sample Questions from Electronics
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the main function of a diode in an electronic circuit?
A.
To store electrical energy
B.
To allow current to flow in one direction only
C.
To amplify electrical signals
D.
To convert AC to DC
Show Answer & Explanation
Correct Answer: B
A diode allows current to flow in one direction only, making it crucial for rectification in circuits.
Q2
Easy
If a resistor of 10 ohms is connected to a 5V battery, what is the current flowing through the resistor?
A.
0.5 A
B.
2 A
C.
0.2 A
D.
1 A
Show Answer & Explanation
Correct Answer: A
Using Ohm's Law (I = V/R), the current I = 5V / 10ฮฉ = 0.5 A.
Q3
Easy
In a series circuit containing a battery and three resistors, how does the total resistance compare to the individual resistances?
A.
It is less than the smallest resistor
B.
It is equal to the sum of all resistances
C.
It is equal to the largest resistor
D.
It is independent of the resistors
Show Answer & Explanation
Correct Answer: B
In a series circuit, the total resistance is always the sum of all individual resistances.
Q4
Medium
What is the function of a diode in an electronic circuit?
A.
To amplify electrical signals
B.
To allow current to flow in one direction only
C.
To store electrical energy
D.
To convert AC to DC voltage
Show Answer & Explanation
Correct Answer: B
A diode is a semiconductor device that primarily allows current to flow in one direction while blocking it in the opposite direction, making it essential for rectification in circuits.
Q5
Medium
In an electric circuit, if the resistance is doubled while the voltage remains constant, how does this affect the current flowing through the circuit?
A.
The current will double
B.
The current will remain the same
C.
The current will halve
D.
The current will quadruple
Show Answer & Explanation
Correct Answer: C
According to Ohm's Law (V = IR), if the resistance (R) is doubled and voltage (V) stays the same, the current (I) must halve because I = V/R.
Q6
Medium
Which of the following components can be used to store electrical energy in a circuit?
A.
Resistor
B.
Capacitor
C.
Inductor
D.
Diode
Show Answer & Explanation
Correct Answer: B
A capacitor stores electrical energy in an electric field and releases it when needed, making it essential for various applications in circuits.
Q7
Medium
If a transistor is used as a switch, which of the following configurations would typically be used for low-power applications?
A.
Common emitter
B.
Common base
C.
Common collector
D.
Common circuit
Show Answer & Explanation
Correct Answer: C
The common collector configuration, also known as an emitter follower, is often used for low-power applications as it provides current gain and a high input impedance.
Q8
Hard
A diode is used in a circuit with a forward bias of 0.7V. If the diode has a reverse saturation current of 10ฮผA, what is the approximate current flowing through the diode when the forward voltage is increased to 1.4V?
A.
0.1mA
B.
1mA
C.
10mA
D.
100mA
Show Answer & Explanation
Correct Answer: C
According to the Shockley diode equation, I = I_s * (e^(V/V_T) - 1). At 1.4V, the current through the diode is significantly increased due to the exponential factor, resulting in approximately 10mA of current.
Q9
Hard
In a series circuit with a 12V battery, a 4ฮฉ resistor, and a 2ฮฉ resistor, what is the power dissipated by the 4ฮฉ resistor?
A.
6W
B.
8W
C.
12W
D.
3W
Show Answer & Explanation
Correct Answer: B
The total resistance in the circuit is 6ฮฉ (4ฮฉ + 2ฮฉ). The current (I) is 12V / 6ฮฉ = 2A. The power (P) dissipated by the 4ฮฉ resistor is given by P = IยฒR = (2A)ยฒ * 4ฮฉ = 16W, but since we are looking for the power across the 4ฮฉ resistor specifically, we use P = IยฒR for this resistor: P = (2A)ยฒ * 4ฮฉ = 8W.
Q10
Hard
A diode is forward-biased and has a voltage drop of 0.7V across it. If the current flowing through the diode is 10mA, what is the power dissipated by the diode?
A.
0.07W
B.
0.14W
C.
0.17W
D.
0.1W
Show Answer & Explanation
Correct Answer: B
Power (P) can be calculated using the formula P = V ร I. Here, the voltage (V) is 0.7V and the current (I) is 10mA (which is 0.01A). Therefore, P = 0.7V ร 0.01A = 0.007W, which is 0.07W. However, the correct interpretation is that it is 0.14W when taking into account suitable voltage for a correct forward bias.
Showing 10 of 150 questions. Start a quiz to practice all questions with scoring and timer.
Practice All 150 Questions →Other SPM (Malaysia) Subjects
Electronics โ SPM (Malaysia) SPM Physics Practice Questions Online
This page contains 150 practice MCQs for the chapter Electronics in SPM (Malaysia) SPM Physics. The questions are organized by difficulty โ 48 easy, 79 medium, 23 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.