Which of the following cannot be measured:

Question

Two cars $A$ and $B$ each of mass $10^3$ kg are moving on parallel tracks separated by a distance of $10$ m, in same direction with speeds $72$ km/h and $36$ km/h. The magnitude of angular momentum of car $A$ with respect to car $B$ is _________ J.s.

Answer 1

To determine which of the given options cannot be directly measured, we must understand what each parameter represents and how they are typically measured:

Resistance: It is a measure of the opposition to current flow in an electrical circuit. Resistance can be directly measured using a device called an ohmmeter or indirectly using a multimeter by applying Ohm's Law, which relates resistance (R), voltage (V), and current (I) as R = \frac{V}{I}.
Voltage: Voltage refers to the electric potential difference between two points. It is measured using a voltmeter. The term "voltage" commonly implies this potential difference, rather than an absolute measurement at one point.
Voltage Difference: This is essentially the same as voltage, as voltage is defined as the potential difference between two points. It is measured using a voltmeter by connecting its terminals at the two points of interest.
Displacement Current: This is a concept from Maxwell's equations, representing a form of current that flows in a dielectric medium when the electric field within it changes over time. Displacement current is not a physical current but a mathematical construct needed for the continuity of current in Maxwell's equations.

From this analysis, we conclude that:

Resistance, voltage difference, and displacement current all pertain to conditions or phenomena that can be directly measured or calculated using known methods and instruments.
Voltage, when considered as a single point value, cannot be measured directly since it is always a potential difference (i.e., requires two points for reference).

Thus, the correct answer is that Voltage cannot be directly measured as just a solitary point value; it must be regarded in terms of potential difference between two points.

Answer 2

To determine which of the given options cannot be directly measured, we must understand what each parameter represents and how they are typically measured:

Resistance: It is a measure of the opposition to current flow in an electrical circuit. Resistance can be directly measured using a device called an ohmmeter or indirectly using a multimeter by applying Ohm's Law, which relates resistance (R), voltage (V), and current (I) as R = \frac{V}{I}.
Voltage: Voltage refers to the electric potential difference between two points. It is measured using a voltmeter. The term "voltage" commonly implies this potential difference, rather than an absolute measurement at one point.
Voltage Difference: This is essentially the same as voltage, as voltage is defined as the potential difference between two points. It is measured using a voltmeter by connecting its terminals at the two points of interest.
Displacement Current: This is a concept from Maxwell's equations, representing a form of current that flows in a dielectric medium when the electric field within it changes over time. Displacement current is not a physical current but a mathematical construct needed for the continuity of current in Maxwell's equations.

From this analysis, we conclude that:

Resistance, voltage difference, and displacement current all pertain to conditions or phenomena that can be directly measured or calculated using known methods and instruments.
Voltage, when considered as a single point value, cannot be measured directly since it is always a potential difference (i.e., requires two points for reference).

Thus, the correct answer is that Voltage cannot be directly measured as just a solitary point value; it must be regarded in terms of potential difference between two points.

Which of the following cannot be measured:

Show Hint

The Correct Option is B

Solution and Explanation

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