Question 1: Current Electricity

Question

Which of the following quantities cannot be directly measured?

Accepted Answer

Resistance is a property of a conductor that opposes the flow of electric current. It can be measured directly using an ohmmeter or calculated using the relation 
R=(V/I)
	​

. Therefore, option (A) is measurable and not the correct answer.

The electric potential at a single point (voltage) represents the work done in bringing a unit positive charge from infinity to that point. Since infinity is taken as an arbitrary reference, the absolute value of voltage at a point cannot be measured directly—it is only a theoretical concept. Hence, voltage is not directly measurable, making option (D) the correct answer.

Voltage difference (potential difference) refers to the difference in electric potential between two points and can be measured using a voltmeter. Therefore, option (B) is measurable and not correct.

Displacement current arises in Maxwell’s equations due to a changing electric field. Although it is not a flow of actual charges, it produces measurable magnetic effects and is therefore considered measurable. Hence, option (C) is also not correct.

$\$Thus, the correct answer is (D) Voltage

Answer

Resistance

Answer

Potential difference

Answer

Displacement current

Answer

Voltage

Current Electricity

Which of the following quantities cannot be directly measured?

Choose the correct answer: