Critical Thinking Questions: Household Circuits

Type I

Assertion & Reason Based Questions

Q1: Assertion: In household wiring, the live wire is also called the phase wire and carries current from the source to the distribution board.
Reason: The phase wire is at a higher potential relative to the earth, which is why it is capable of carrying current to the distribution board.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) Both the assertion and the reason are true, but the reason is not a correct explanation of the assertion. 
(c) The assertion is true, but the reason is false. 
(d) The assertion is false, but the reason is true.

Q2: Assertion: The fuse in an electrical circuit is always connected in the neutral wire.
Reason: The fuse is designed to melt and break the circuit if the current exceeds a safe limit, preventing damage to the appliances and circuit.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) The assertion is true, but the reason is false. 
(c) The assertion is false, but the reason is true. 
(d) Both the assertion and the reason are false.

Q3: Assertion: The thickness of a fuse wire depends on its current rating.
Reason: A thicker fuse wire has a larger cross-sectional area which dissipates heat more effectively.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) Both the assertion and the reason are true, but the reason is not a correct explanation of the assertion. 
(c) The assertion is true, but the reason is false. 
(d) The assertion is false, but the reason is true.

Q4: Assertion: It is safe to carry out repairs on an appliance when the switch in the live wire is in the 'off' position.
Reason: When the switch in the live wire is off, the appliance is disconnected from the high potential terminal, and the circuit is incomplete, which prevents current from flowing.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) Both the assertion and the reason are true, but the reason is not a correct explanation of the assertion. 
(c) The assertion is true, but the reason is false. 
(d) The assertion is false, but the reason is true.

Q5: Assertion: Double pole switches are used in staircases to allow control of a light from two different places.
Reason: Double pole switches disconnect both the live and neutral wires simultaneously, which is a requirement for staircase lighting circuits.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) The assertion is true, but the reason is false. 
(c) The assertion is false, but the reason is true. 
(d) Both the assertion and the reason are false.

Q6: Assertion: In a household ring system, each appliance is provided with a separate fuse for protection.
Reason: A separate fuse for each appliance ensures that if one appliance fails, it does not affect the circuitry of the other appliances.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) The assertion is true, but the reason is false. 
(c) The assertion is false, but the reason is true. 
(d) Both the assertion and the reason are false.

Q7: Assertion: Fuses are always connected in the neutral wire of the circuit.
Reason: The fuse needs to melt when the current exceeds the safe limit, interrupting the circuit.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) The assertion is true, but the reason is false. 
(c) The assertion is false, but the reason is true. 
(d) Both the assertion and the reason are false.

Q8: Assertion: Local earthing is performed to provide a low-resistance path for electric current to flow into the ground.
Reason: A thick copper plate surrounded by a mixture of charcoal and salt is used in local earthing because it increases the resistivity of the soil.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) The assertion is true, but the reason is false. 
(c) The assertion is false, but the reason is true. 
(d) Both the assertion and the reason are false.

Q9: Assertion: The colour coding of wires in a cable is essential for safety and to prevent electrical hazards.
Reason: In the new international convention for wire colour coding, the live wire is brown, the neutral wire is light blue, and the earth wire is green or yellow.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) Both the assertion and the reason are true, but the reason is not a correct explanation of the assertion. 
(c) The assertion is true, but the reason is false. 
(d) The assertion is false, but the reason is true.

Q10: Assertion: A three-pin plug is designed in such a way that the earth pin is longer and thicker than the other two pins.
Reason: The longer earth pin ensures that the earth connection is made first and breaks last for safety reasons.
(a) Both the assertion and the reason are true, and the reason is a correct explanation of the assertion. 
(b) The assertion is true, but the reason is false. 
(c) The assertion is false, but the reason is true. 
(d) Both the assertion and the reason are false.

Type II

Statements Based Questions

Q11: Statement 1: The resistance of a wire is inversely proportional to its length. 
Statement 2: The resistance of a wire is directly proportional to its cross-sectional area. 
Statement 3: The resistance of a wire increases with an increase in temperature.
(a) Only 1 
(b) Only 2 
(c) Only 1 and 3 
(d) All 1, 2, and 3

Q12: Statement 1: In a series circuit, the current through each component is the same. 
Statement 2: The total resistance in a parallel circuit is equal to the sum of individual resistances. 
Statement 3: The voltage across each component in a parallel circuit is the same.
(a) Only 1 and 3 
(b) Only 2 
(c) Only 1 
(d) Only 3

Q13: Statement 1: Ohm's Law states that the current through a conductor is directly proportional to the voltage across it. 
Statement 2: The SI unit of resistivity is ohm-meter. 
Statement 3: Power dissipated in a resistor is given by $P\; =\; IV$P= IV, where I is current, and V is voltage.
(a) Only 1 and 2 
(b) Only 3 
(c) Only 1 and 3 
(d) All 1, 2, and 3

Q14: Statement 1: Capacitors store electrical energy in an electric field. 
Statement 2: The capacitance of a parallel-plate capacitor increases with the distance between the plates. 
Statement 3: Energy stored in a capacitor is given by (1/2CV²), where C is capacitance and V is voltage.
(a) Only 1 and 3 
(b) Only 1 
(c) Only 2 
(d) Only 3

Q15: Statement 1: The unit of electric charge is the Coulomb. 
Statement 2: The electric potential at a point is defined as the work done in moving a unit positive charge from infinity to that point. 
Statement 3: Electric field is a vector quantity, and its direction is from positive to negative charge.
(a) Only 2 and 3 
(b) Only 1 and 2 
(c) Only 1 
(d) All 1, 2, and 3

Q16: A 10-ohm resistor is connected to a 5V battery. Which of the following is true?
Statement 1: The current through the resistor is 0.5A. 
Statement 2: The power dissipated by the resistor is 2.5W. 
Statement 3: The energy dissipated in 10 seconds is 25 Joules.
(a) Only 1 
(b) Only 1 and 2 
(c) Only 2 and 3 
(d) All 1, 2, and 3

Q17: Statement 1: A magnetic field can influence the movement of a toy car with a magnet attached, rolling near a strong magnet. 
Statement 2: If the toy car moves towards the magnet, the direction of the force acting on it due to the magnetic field is directly towards or away from the strong magnet. 
Statement 3: If the toy car moves along the magnetic field lines of the strong magnet, the field can change its speed but not its direction.
(a) Only 1 and 2 
(b) Only 2 
(c) Only 1 
(d) All 1, 2, and 3

Q18: Statement 1: The standard frequency of an alternating current (AC) in India is 60 Hz. 
Statement 2: In a direct current (DC) circuit, the current flows in one direction only. 
Statement 3: The root mean square (RMS) value of an AC is equal to its peak value divided by √2.
(a) Only 1 and 2 
(b) Only 2 and 3 
(c) Only 1 
(d) All 1, 2, and 3

Q19: Statement 1: The main household circuits is a switch in household circuits is a single pole switch.
Statement 2: The main fuse in a household circuit is connected in the live wire. 
Statement 3: The earth wire in a household circuit is at a high potential.
(a) Only 2 
(b) Only 1 and 3 
(c) Only 2 and 3 
(d) All 1, 2, and 3

Q20: Statement 1: A three-pin plug's earth pin is thicker and longer than the other pins. 
Statement 2: The colour coding for the earth wire in a cable is red. 
Statement 3: In India, the live wire in a three-pin plug is usually connected to the left pin.
(a) Only 1 
(b) Only 1 and 3 
(c) Only 2 and 3 
(d) All 1, 2, and 3