Physics for IGCSE & O level - Electricity (Section 11)
1
In a parallel circuit, if one branch has a resistance of 10 ohms, and another branch has a resistance of 20 ohms, which branch will have more current flowing through it?
คำตอบ
(A)
The 10-ohm branch
2
How does the diameter of a wire affect its resistance?
คำตอบ
(A)
Larger diameter = lower resistance
3
What is the unit of measurement for the amount of electrical charge?
คำตอบ
(C)
Coulomb
4
What is the effect on the total resistance of a circuit if a parallel branch is added with a very high resistance?
คำตอบ
(C)
The total resistance stays almost the same.
5
What is the function of an LED?
คำตอบ
(B)
To produce light when current flows through it
6
In a series circuit, where are the components connected?
คำตอบ
(B)
one after the other in a single path
7
What happens to the current if the voltage increases while the resistance stays constant?
คำตอบ
(B)
The current increases.
8
Which items are described as conductors?
คำตอบ
A
B
C
9
What is the term for the opposition to the flow of current in an electrical circuit?
คำตอบ
(C)
Resistance
10
What is the equivalent resistance of two 2-ohm resistors in series?
คำตอบ
(D)
4 ohms
11
Which of the following electrical hazards can cause serious injury or death?
คำตอบ
A
B
C
12
In a parallel circuit, if one resistor breaks, what happens to the other resistors?
คำตอบ
(C)
They continue to function.
13
What does the letter "I" represent in electrical circuits?
คำตอบ
(A)
Current
14
What type of current does a battery typically supply?
คำตอบ
(B)
Direct Current (DC)
15
What should you do if a wireless appliance electrocutes someone?
คำตอบ
(C)
Pull the plug if it is safe to do so, and call for help.
16
What happens when the filament temperature increases?
คำตอบ
(A)
Resistance increases
17
What is the unit for measuring electrical frequency?
คำตอบ
(C)
Hertz
18
What is the purpose of a step-down transformer?
คำตอบ
(B)
To decrease the voltage
19
Which type of resistor is affected by the amount of light shining on it?
คำตอบ
(C)
Light Dependent Resistor
20
Which of the following is a good conductor of electricity?
คำตอบ
(C)
Copper
21
What unit is used to measure electrical energy?
คำตอบ
(C)
Joule
22
Which materials would be considered as insulators?
คำตอบ
(C)
Rubber
23
What kind of current is used in the main electrical grid?
คำตอบ
(B)
Alternating current
24
What happens if you add more resistors in series?
คำตอบ
(C)
The overall resistance increases.
25
What flows through a wire to make an electric circuit work?
คำตอบ
(A)
Electrons
26
If two equal resistors are connected in parallel, the equivalent resistance is:
คำตอบ
(C)
Half the value of a single resistor
27
How is electrical power calculated?
คำตอบ
(A)
P = V x I
28
In a parallel circuit, how is the total current related to the current in each branch?
คำตอบ
(B)
The total current is the sum of the branch currents.
29
If a device uses 100 watts of power and is connected to a 230V supply, what is the current?
คำตอบ
(A)
0.43 A
30
Which type of energy is typically transformed by a light bulb?
คำตอบ
(B)
Electrical to light and heat
31
What is the name of the law that relates voltage, current, and resistance?
คำตอบ
(B)
Ohm's Law
32
How does the cross-sectional area of a conductor affect its resistance?
คำตอบ
(B)
Smaller area means higher resistance
33
What is the frequency of the mains electricity in most countries?
คำตอบ
(A)
50 Hz
34
What type of material has more resistance?
คำตอบ
(B)
Nichrome
35
If two resistors (R1 and R2) are in parallel, what happens to the current in each resistor?
คำตอบ
A
D
36
In a parallel circuit, how is the total current calculated?
คำตอบ
(C)
By summing the individual currents in each branch.
37
What formula is associated with Ohm's Law?
คำตอบ
(B)
V = IR
38
What is the relationship between potential difference and current in a metallic conductor at constant temperature?
คำตอบ
(A)
Directly proportional
39
If a 12V battery is connected to a 6-ohm resistor, what is the current flowing through the resistor?
คำตอบ
(B)
6 Amps
40
Which of these is NOT a common electrical hazard?
คำตอบ
(D)
Magnetic fields
41
What is the purpose of a light bulb filament?
คำตอบ
(C)
To produce light
42
What is the combined resistance of 10, 20, and 30 ohms resistors in series?
คำตอบ
(A)
60 ohms
43
What is the SI unit of electric charge?
คำตอบ
(D)
Coulomb
44
What is the formula for Ohm's Law?
คำตอบ
(C)
V = I * R
45
What is the unit of measurement for electrical power?
คำตอบ
(D)
Watt
46
What is the primary function of an ammeter in a circuit?
คำตอบ
(B)
To measure current
47
If two resistors are connected in parallel with equal resistances, the current will be:
คำตอบ
(A)
The same through both resistors
48
What happens to the current in a parallel circuit when a bulb burns out?
คำตอบ
(C)
The total current remains the same.
49
Which of the following is a unit of electrical power?
