Current Electricity

Topics in this chapter

• Current Flow and Resistance
• Resistor Networks and Circuit Laws
• Cells, EMF, and Internal Resistance
• Electrical Measurement Methods
• Electrical Power and Temperature Effects

Cheat sheet

Practice questions

1. Question 1Q-C604B2

   A current of $2\text{ A}$ flows through a 2 ohm resistor when connected across a potential difference. The total charge passing through any cross-section of the resistor in $5\text{ seconds}$ is:

   1. A.2.5 C
   2. B.10 C
   3. C.20 C
   4. D.0.4 C
   See the answer and solution
2. Question 2Q-89F347

   A uniform wire of resistance $R$ is stretched uniformly to double its original length. The new resistance of the wire will be:

   1. A.2R
   2. B.4R
   3. C.R/2
   4. D.R/4
   See the answer and solution
3. Question 3Q-FDF9F7

   The drift velocity of free electrons in a metallic conductor is $v_d$ when a current $I$ flows through it. If the current is increased to $2I$, the drift velocity becomes:

   1. A.v_d / 2
   2. B.v_d
   3. C.2v_d
   4. D.4v_d
   See the answer and solution
4. Question 4Q-E04B0A

   Kirchhoff's first law (junction rule) and second law (loop rule) are based on the conservation of respectively:

   1. A.Energy and Charge
   2. B.Charge and Energy
   3. C.Momentum and Energy
   4. D.Energy and Momentum
   See the answer and solution
5. Question 5Q-DA1BD8

   A cell of emf $E$ and internal resistance $r$ is connected across an external resistance $R$. The maximum power is delivered to the external resistance when:

   1. A.R = r
   2. B.R = 2r
   3. C.R = r/2
   4. D.R >> r
   See the answer and solution