The potential difference \((V_A - V_B)\) between the points \(A\) and \(B\) in the given figure is
- -3 V
+3 V
+6 V
+9 V
The Correct Option is D
Solution and Explanation
Answer: 9 V
Explanation:
In the diagram:
- The battery is 18 V.
- There are two resistors of 3 Ω and 3 Ω in series between A and B.
Since both resistors are of equal value, the voltage drop is equally divided.
- Total resistance = 3 Ω + 3 Ω = 6 Ω
- Current in the circuit = \(I = \frac{V}{R} = \frac{18}{6} = 3 \, \text{A}\)
- Potential drop across each 3 Ω resistor = \(V = IR = 3 \times 3 = 9 \, \text{V}\)
Hence, potential at A is 18 V and after one resistor (3 Ω), it drops 9 V. Therefore,
\(V_A - V_B = 9 \, \text{V}\)
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Concepts Used:
Electric Current
Defining Electric Current
It is the rate of flow of electrons in a conductor. SI Unit - Ampere (A).
Electrons are negatively charged particles hence when they move a number of charges moves.
Note:- The ability of a particular substance to conduct electricity depends on the number of electrons that are able to move . Some of the materials allow current to flow better than others.
What is an Electromotive Force?
If a force acts on electrons to make them move in a particular direction, then up to some extent random motion of the electrons will be eliminated. An overall movement in one direction. The force which acts on the electrons to move them in a certain direction is known as electromotive force and its quantity is known as voltage and is measured in V.