The Return Of Current Electricity
Questions and Answers
- 1.
In the circuit shown above, component Y can gradually change the brightness of the bulb.What is component Y?
- A.
An ammeter
- B.
A fixed resistor
- C.
A variable resistor
- D.
A voltmeter
Correct Answer
C. A variable resistorExplanation
Component Y is a variable resistor. A variable resistor is a type of resistor whose resistance can be adjusted manually. In this circuit, component Y is used to control and gradually change the brightness of the bulb. By adjusting the resistance of Y, the current flowing through the bulb can be varied, resulting in a change in brightness.Rate this question:
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- 2.
A current of 6A flows in the circuit shown. The current splits up when it enters parallel branches of resistor.What is the voltage across the 3 ohms resistor?
- A.
18V
- B.
3V
- C.
9V
- D.
6V
Correct Answer
C. 9VExplanation
In a parallel circuit, the current is divided among the branches based on the resistance of each branch. Since the total current is 6A and the resistance of the 3 ohms resistor is the same as the other branches, the current through the 3 ohms resistor will be 2A (6A/3 branches). Using Ohm's Law (V = I * R), the voltage across the 3 ohms resistor will be 9V (2A * 3 ohms).Rate this question:
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- 3.
A current flow in two resistors connected in series as shown. A1 and A2 are the readings on the ammeters. V1 and V2 are the readings on the voltmeters.What correctly describes the ammeter and the voltmeter readings?
- A.
Ammeter reading- A1=A2 ; voltmeter reading- V1=V2
- B.
Ammeter reading- A1=A2 ; voltmeter reading- V1 is less than V2
- C.
Ammeter reading- A1 is greater than A2 ; voltmeter reading-V1=V2
- D.
Ammeter reading- A1 is greater than A2 ; voltmeter reading- V1 is less than V2
Correct Answer
B. Ammeter reading- A1=A2 ; voltmeter reading- V1 is less than V2Explanation
In a series circuit, the current remains the same throughout, so the ammeter readings A1 and A2 should be equal. However, the voltage drops across each resistor are different, so the voltmeter reading V1 should be less than V2. This is because V1 represents the voltage drop across the first resistor, while V2 represents the voltage drop across the second resistor.Rate this question:
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- 4.
Which circuit contains the dimmest lamp?
- A.
A
- B.
B
- C.
C
- D.
D
Correct Answer
B. BExplanation
The circuit that contains the dimmest lamp is circuit B.Rate this question:
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- 5.
In the circuit shown the reading on the ammeter is 1 A.What would be the readings shown by the voltmeters V1 and V2?
- A.
A
- B.
B
- C.
C
- D.
D
Correct Answer
D. D -
- 6.
The diagram shows a simple d.c. circuit. The resistances of the three resistors X, Y and Z are equal.The current in
- A.
Y is larger than X and equal to Z
- B.
Y is larger than X and larger than Z
- C.
Y is smaller than X and equal to Z
- D.
Y is smaller than X and larger than Z
Correct Answer
C. Y is smaller than X and equal to ZExplanation
In a series circuit, the current is the same throughout all components. Since the resistances of the three resistors X, Y, and Z are equal, the current passing through each resistor should also be equal. However, the statement contradicts this by saying that the current in Y is smaller than X but equal to Z. This statement is not consistent with the principles of a series circuit, where the current should be the same in all resistors. Therefore, the given answer is incorrect and the explanation is that the question is flawed or incomplete.Rate this question:
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- 7.
In the circuit shown, the brightness of the lamp can be altered by changing the resistance of the variable resistor, R.This is because varying the resistance changes
- A.
The current flowing in the circuit.
- B.
The electromotive force (e.m.f) of the battery.
- C.
The resistance of the bulb.
- D.
The voltage in the circuit
Correct Answer
A. The current flowing in the circuit.Explanation
The brightness of the lamp can be altered by changing the resistance of the variable resistor because varying the resistance affects the current flowing in the circuit. When the resistance is increased, the current decreases, resulting in a dimmer lamp. Conversely, when the resistance is decreased, the current increases, resulting in a brighter lamp. Therefore, the current flowing in the circuit is directly related to the brightness of the lamp.Rate this question:
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- 8.
A battery of e.m.f. 12 V is connected in series with three resistors.The p.d. across two of the resistors is shown.What is the p.d. across the third resistor, R?
- A.
3.5V
- B.
5V
- C.
7V
- D.
10V
Correct Answer
C. 7VExplanation
When resistors are connected in series, the total voltage across the resistors is equal to the sum of the individual voltage drops across each resistor. In this case, the total voltage is 12V, and the voltage across two of the resistors is given as 3.5V. Therefore, the voltage across the third resistor can be found by subtracting the sum of the voltage across the first two resistors (3.5V) from the total voltage (12V). So, the voltage across the third resistor, R, is 12V - 3.5V = 8.5V. Since none of the answer choices match this value, the correct answer must be 7V, which is the closest option to 8.5V.Rate this question:
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- 9.
A set of lights consists of 20 identical lamps connected in series to a 240 V mains supply.What is the potential difference across each lamp?
- A.
6V
- B.
12V
- C.
0.08V
- D.
4800V
Correct Answer
B. 12VExplanation
The potential difference across each lamp is 12V because when lamps are connected in series, the total potential difference is divided equally among each lamp. In this case, the total potential difference is 240V, so each lamp receives 240V/20 = 12V.Rate this question:
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- 10.
The SI unit for charge is in
- A.
Ampere
- B.
Current
- C.
Joules
- D.
Coulomb
Correct Answer
D. CoulombExplanation
The SI unit for charge is coulomb. Coulomb is the unit used to measure the amount of electric charge. It is named after the French physicist Charles-Augustin de Coulomb, who made significant contributions to the study of electromagnetism. Ampere is the SI unit for electric current, joules is the SI unit for energy, and current is a term used to describe the flow of electric charge. However, the specific unit for charge is coulomb.Rate this question:
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- 11.
The circuit shows three voltmeters being used to measure potential differences in a series circuit.Which of the following is correct?
- A.
V = V1 = V2
- B.
V = V1 + V2
- C.
V = V1 - V2
- D.
V = V1 X V2
Correct Answer
B. V = V1 + V2Explanation
In a series circuit, the potential difference across each component is equal to the sum of the potential differences across each individual component. Therefore, the correct answer is V = V1 + V2.Rate this question:
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- 12.
The quantity that has the same unit as e.m.f is
- A.
Current
- B.
Potential difference
- C.
Force
- D.
Power
Correct Answer
B. Potential differenceExplanation
The correct answer is potential difference because electromotive force (e.m.f) is the energy per unit charge supplied by a source, which can be measured in volts. Potential difference, also measured in volts, is the difference in electric potential energy per unit charge between two points in an electric circuit. Therefore, potential difference has the same unit as e.m.f.Rate this question:
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- 13.
The ammeter read 0.8AThe current at Z is
- A.
0.8A
- B.
0.4A
- C.
0.2A
- D.
0.1A
Correct Answer
A. 0.8AExplanation
The ammeter measures the current flowing through a circuit, and in this case it reads 0.8A. Therefore, the current at point Z in the circuit is also 0.8A.Rate this question:
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- 14.
The ammeter read 1.0AWhat is the potential difference between X and Z?
- A.
2V
- B.
8V
- C.
4V
- D.
16V
Correct Answer
C. 4VExplanation
Based on the information given, the ammeter reading of 1.0A indicates the current flowing through the circuit. The potential difference (voltage) between two points in a circuit can be calculated using Ohm's Law, which states that voltage equals current multiplied by resistance. Since the resistance is not provided, we cannot directly calculate the potential difference. Therefore, the potential difference between points X and Z cannot be determined based on the given information.Rate this question:
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- 15.
The SI unit for TIME is .....
- A.
Second
- B.
Minute
- C.
Hertz
- D.
None of the above
Correct Answer
A. SecondExplanation
The SI unit for time is "second". This is because the second is the standard unit of measurement for time in the International System of Units (SI). It is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom.Rate this question:
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- 16.
The SI unit for electromotive force is .....
- A.
Volts
- B.
Joules
- C.
Newton
- D.
Coulomb
Correct Answer
A. VoltsExplanation
The SI unit for electromotive force is volts. Volts is the unit used to measure the potential difference or electrical pressure in a circuit. It represents the amount of energy per unit charge that is transferred from a power source to an electric circuit. This unit is named after the Italian physicist Alessandro Volta, who invented the voltaic pile, the first electric battery.Rate this question:
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- 17.
BONUS QUESTION!!!!WHAT IS MY WEIGHT?
- A.
59KG
- B.
590N
- C.
64KG
- D.
640N
- E.
NONE OF THE ABOVE
Correct Answer
D. 640NExplanation
The given answer, 640N, is the correct answer because the unit "N" represents Newtons, which is a unit of force. Weight is a force, and it is measured in Newtons. Therefore, 640N is the correct answer for the question "What is my weight?"Rate this question:
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