Q. A wire has a resistance of 12 Ω and is made of a material with a resistivity of 3 x 10^-6 Ω·m. If the length of the wire is 4 m, what is its cross-sectional area?
Q. A wire made of material A has a resistivity of 1.5 x 10^-8 Ω·m, while material B has a resistivity of 3.0 x 10^-8 Ω·m. If both wires have the same dimensions, which wire will have a higher resistance?
A.
Wire A
B.
Wire B
C.
Both have the same resistance
D.
Cannot be determined
Solution
Resistance is directly proportional to resistivity; hence, wire B with higher resistivity will have higher resistance.
Q. A wire made of material A has twice the length and half the cross-sectional area of a wire made of material B. If the resistivity of A is ρ, what is the resistance of wire A in terms of the resistance of wire B?
A.
2R
B.
4R
C.
R/2
D.
R/4
Solution
Resistance R = ρ(L/A). For wire A, R_A = ρ(2L/(A/2)) = 4ρ(L/A) = 4R_B.
Q. According to Kirchhoff's Current Law, if three currents enter a junction as 2A, 3A, and 4A, what is the current leaving the junction?
A.
1A
B.
3A
C.
5A
D.
9A
Solution
According to Kirchhoff's Current Law, the sum of currents entering a junction equals the sum of currents leaving. Therefore, I_out = 2A + 3A + 4A = 9A.
Q. According to Kirchhoff's Current Law, if three currents entering a junction are 2A, 3A, and 5A, what is the total current leaving the junction?
A.
10A
B.
5A
C.
3A
D.
2A
Solution
According to Kirchhoff's Current Law, the total current entering a junction equals the total current leaving it. Therefore, total current leaving = 2A + 3A + 5A = 10A.
Q. If a 5 ohm resistor and a 10 ohm resistor are connected in series, what is the voltage across the 10 ohm resistor when a current of 2 A flows through the circuit?
A.
10 V
B.
20 V
C.
5 V
D.
15 V
Solution
Voltage across the 10 ohm resistor, V = I * R = 2 A * 10 Ω = 20 V.
Current Electricity is a crucial topic in physics that students must master for their exams. Understanding this concept not only helps in grasping fundamental principles but also significantly boosts your performance in objective questions. Practicing MCQs and important questions related to Current Electricity can enhance your exam preparation and increase your chances of scoring higher marks.
What You Will Practise Here
Ohm's Law and its applications
Series and parallel circuits
Electrical power and energy calculations
Resistance, resistivity, and factors affecting resistance
Kirchhoff's laws and their practical applications
Concept of current, voltage, and their relationship
Diagrams and circuit analysis techniques
Exam Relevance
The topic of Current Electricity is frequently tested in various examinations, including CBSE, State Boards, NEET, and JEE. Students can expect questions that assess their understanding of fundamental concepts, application of formulas, and problem-solving skills. Common question patterns include numerical problems, theoretical questions, and circuit analysis, making it essential to be well-prepared with Current Electricity MCQ questions.
Common Mistakes Students Make
Confusing current with voltage and their units
Misapplying Ohm's Law in complex circuits
Overlooking the effects of temperature on resistance
Failing to differentiate between series and parallel connections
Neglecting to draw circuit diagrams for better understanding
FAQs
Question: What is the formula for calculating electrical power? Answer: The formula for electrical power is P = VI, where P is power, V is voltage, and I is current.
Question: How does resistance change in series and parallel circuits? Answer: In series circuits, total resistance increases, while in parallel circuits, total resistance decreases.
Now is the time to enhance your understanding of Current Electricity! Dive into our practice MCQs and test your knowledge to ensure you are well-prepared for your exams. Start solving today and boost your confidence!
Soulshift Feedback×
On a scale of 0–10, how likely are you to recommend
The Soulshift Academy?
