Critical Thinking Questions: Current Electricity

Type I

Assertion & Reason Based Questions

Q1: Assertion: Ohm's law is applicable to all materials regardless of their temperature and physical state.
Reason: Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
(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.

Q2: Assertion: A volt is the unit of electric current.
Reason: The S.I. unit of electric potential is the volt, which is defined as the work done per unit charge in moving a charge from infinity to a given point.
(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: Ohmic resistors do not have a V-I graph that is a straight line passing through the origin.
Reason: Ohmic resistors follow Ohm's Law, which states that the current through the resistor is directly proportional to the potential difference across it at constant temperature.
(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: Specific resistance of a material is independent of the physical dimensions of the material.
Reason: Specific resistance, or resistivity, is an intrinsic property of the material and is not affected by the shape or size of the material sample.
(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.

Q5: Assertion: The electromotive force (e.m.f.) of a cell is independent of the amount of charge flowing through it.
Reason: E.m.f. is measured by the energy supplied to each coulomb of charge to move through the cell, not by the total amount of charge.
(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: The total resistance of a combination of resistors both in series and in parallel can be less than the smallest individual resistance in the circuit.
Reason: Combining resistors in parallel reduces the total resistance below the smallest individual resistance, and adding a series element can increase the total resistance but not above the smallest individual resistance.
(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: The current through each resistor in a series circuit is different.
Reason: In a series circuit, the total current is divided among the resistors in proportion to their resistances.
(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: The electrical energy consumed by a resistor can be calculated using the formula W=V²t/R.
Reason: This formula is derived from the power expression $P\; =\; V^2/R$P= V²/R, which is based on Ohm's law $V\; =\; IR$V= IR, and energy is power integrated over time.
(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: A kilowatt-hour is a unit of power.
Reason: Power is the rate at which energy is consumed or produced.
(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.

Q10: Assertion: The safe current through an appliance can be calculated using the power rating and the voltage rating of the appliance.
Reason: The safe current is inversely proportional to the voltage rating of the appliance.
(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: Ohm's Law states V= IR, where V is the potential difference, I is the current, and R is the resistance. 
Statement 2: Resistance in a wire is inversely proportional to its cross-sectional area. 
Statement 3: The unit of electric current is Coulomb per second.
(a) Only 1 
(b) Only 2 
(c) 1 and 3 
(d) All 1, 2, and 3

Q12: Statement 1: The resistance of a conductor increases with an increase in temperature. 
Statement 2: In a parallel circuit, the total resistance is less than the smallest individual resistance. 
Statement 3: A current of 1 A flowing through a wire indicates 1 C of charge passing through it per minute.
(a) Only 1 
(b) 1 and 2 
(c) 2 and 3 
(d) All 1, 2, and 3

Q13: Statement 1: Superconductors are materials that exhibit zero resistance at very low temperatures. 
Statement 2: The potential difference is measured in Joules. 
Statement 3: The specific resistance of a material is independent of its physical dimensions.
(a) Only 1 
(b) 1 and 3 
(c) Only 3 
(d) All 1, 2, and 3

Q14: Statement 1: Conductors that obey Ohm's Law are known as ohmic resistors. 
Statement 2: In metallic conductors, the flow of current is due to the movement of electrons. 
Statement 3: The electric potential is a vector quantity.
(a) Only 2 
(b) 1 and 2 
(c) 2 and 3 
(d) All 1, 2, and 3

Q15: Statement 1: A wire of resistance 5 Ω carries a current of 1 A, the potential difference across it is 5 V. 
Statement 2: If the length of the wire is doubled, the resistance becomes 10 Ω. 
Statement 3: Doubling the cross-sectional area of the wire halves its resistance.
(a) Only 1 
(b) 1 and 3 
(c) 2 and 3 
(d) All 1, 2, and 3

Q16: Statement 1: A current of 2 A flowing through a 4 Ω resistor will produce 8 V across it. 
Statement 2: If the current is halved, the voltage drop becomes 4 V. 
Statement 3: Tripling the resistance with the original current produces a voltage drop of 24 V.
(a) Only 1 
(b) 1 and 3 
(c) Only 2 
(d) All 1, 2, and 3

Q17: Statement 1: The potential difference between two points is defined as the work done per unit charge. 
Statement 2: Electric power is measured in Watts and is calculated as P = VI. 
Statement 3: The direction of electric current is from lower to higher potential.
(a) Only 2 
(b) 1 and 2 
(c) 2 and 3 
(d) All 1, 2, and 3

Q18: Statement 1: If a wire of resistance 5 Ohms is connected across a battery of 10V, the current through the wire is 2A. 
Statement 2: Using Ohm's law, the resistance of a wire through which 0.5A flows when connected to a 5V battery is 100 Ohms. 
Statement 3: For a 12V battery and a wire of resistance 4 Ohms, the current through the circuit is 3A.
(a) Only 1 and 2 
(b) Only 1 and 3 
(c) Only 1 
(d) All 1, 2 and 3

Q19: Statement 1: Ohmic resistors have a linear V-I (Voltage-Current) relationship. 
Statement 2: Non-ohmic resistors exhibit a nonlinear V-I relationship. 
Statement 3: The resistance of an ohmic resistor does not change with temperature.
(a) Only 1 and 2 
(b) Only 1 and 3 
(c) Only 2 and 3 
(d) All 1, 2, and 3

Q20: Statement 1: The electric potential at a point is defined as the work done per unit charge in bringing a positive test charge from infinity to that point. 
Statement 2: Potential difference between two points is the work done to move a unit charge from one point to another. 
Statement 3: The unit of potential difference is Joule per Coulomb.
(a) Only 1 
(b) Only 1 and 2 
(c) Only 2 and 3 
(d) All 1, 2, and 3