Q. If the resistance values in a Wheatstone bridge are all equal, what is the condition for balance?
A.
All resistances must be zero
B.
Any resistance can be changed
C.
The bridge is always balanced
D.
The bridge is never balanced
Show solution
Solution
If all resistances are equal, the bridge is always balanced regardless of the values.
Correct Answer:
C
— The bridge is always balanced
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Q. If the resistance values in a Wheatstone bridge are doubled, what happens to the balance condition?
A.
It remains the same
B.
It becomes unbalanced
C.
It becomes easier to balance
D.
It becomes impossible to balance
Show solution
Solution
Doubling all resistance values does not affect the balance condition, as the ratios remain the same.
Correct Answer:
A
— It remains the same
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Q. If the resistance values in a Wheatstone bridge are R1 = 10Ω, R2 = 15Ω, R3 = 5Ω, what should R4 be for the bridge to be balanced?
A.
7.5Ω
B.
10Ω
C.
12.5Ω
D.
15Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we find R4 = (R2 * R3) / R1 = (15 * 5) / 10 = 7.5Ω.
Correct Answer:
C
— 12.5Ω
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Q. If the resistance values in a Wheatstone bridge are R1 = 10Ω, R2 = 20Ω, R3 = 15Ω, what is the value of R4 for the bridge to be balanced?
A.
30Ω
B.
15Ω
C.
10Ω
D.
5Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we find R4 = (R2 * R3) / R1 = (20 * 15) / 10 = 30Ω.
Correct Answer:
B
— 15Ω
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Q. If the resistances in a Wheatstone bridge are 10Ω, 20Ω, 30Ω, and 60Ω, what is the value of the unknown resistance?
A.
15Ω
B.
25Ω
C.
30Ω
D.
45Ω
Show solution
Solution
Using the formula R1/R2 = R3/R4, we find that R4 = (R2 * R3) / R1 = (20 * 30) / 10 = 60Ω.
Correct Answer:
B
— 25Ω
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Q. If the resistances in a Wheatstone bridge are 4Ω, 8Ω, 12Ω, and R, what is the value of R for the bridge to be balanced?
A.
6Ω
B.
8Ω
C.
10Ω
D.
12Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we find R = (R2 * R3) / R1 = (8 * 12) / 4 = 24Ω.
Correct Answer:
A
— 6Ω
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Q. If the resistances in a Wheatstone bridge are 5Ω, 15Ω, 10Ω, and R, what is the value of R for the bridge to be balanced?
A.
7.5Ω
B.
10Ω
C.
12.5Ω
D.
15Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we find R = (R2 * R3) / R1 = (15 * 10) / 5 = 30Ω.
Correct Answer:
C
— 12.5Ω
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Q. If the resistances in a Wheatstone bridge are equal, what is the current through the galvanometer?
A.
Zero
B.
Maximum
C.
Minimum
D.
Depends on the voltage
Show solution
Solution
If all resistances are equal, the bridge is balanced and the current through the galvanometer is zero.
Correct Answer:
A
— Zero
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Q. If the resistances in a Wheatstone bridge are equal, what is the potential difference across the galvanometer?
A.
Zero
B.
Equal to the supply voltage
C.
Half of the supply voltage
D.
Depends on the resistances
Show solution
Solution
If the resistances are equal, the potential difference across the galvanometer is zero.
Correct Answer:
A
— Zero
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Q. If the resistances in a Wheatstone bridge are P = 10Ω, Q = 15Ω, R = 5Ω, and S = xΩ, what is the value of x for the bridge to be balanced?
A.
7.5Ω
B.
10Ω
C.
12.5Ω
D.
15Ω
Show solution
Solution
For balance, P/Q = R/S => 10/15 = 5/x => x = 7.5Ω.
Correct Answer:
C
— 12.5Ω
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Q. If the resistances in a Wheatstone bridge are P = 3Ω, Q = 6Ω, R = 1.5Ω, and S = 3Ω, is the bridge balanced?
A.
Yes
B.
No
C.
Cannot be determined
D.
Only if P = R
Show solution
Solution
The bridge is not balanced because P/Q ≠ R/S.
Correct Answer:
B
— No
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Q. If the resistances in a Wheatstone bridge are R1 = 10Ω, R2 = 15Ω, R3 = 5Ω, and R4 = xΩ, what value of x will balance the bridge?
A.
7.5Ω
B.
10Ω
C.
12.5Ω
D.
15Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we have 10/15 = 5/x, solving gives x = 7.5Ω.
Correct Answer:
A
— 7.5Ω
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Q. If the resistances in a Wheatstone bridge are R1 = 10Ω, R2 = 15Ω, R3 = 5Ω, and R4 = 7.5Ω, is the bridge balanced?
A.
Yes
B.
No
C.
Depends on the voltage
D.
Not enough information
Show solution
Solution
The bridge is balanced if R1/R2 = R3/R4. Here, 10/15 = 5/7.5, which simplifies to 2/3 = 2/3, confirming the bridge is balanced.
Correct Answer:
A
— Yes
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Q. If the resistances in a Wheatstone bridge are R1 = 10Ω, R2 = 15Ω, R3 = 5Ω, what is the value of R4 for the bridge to be balanced?
A.
7.5Ω
B.
10Ω
C.
12.5Ω
D.
15Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we have 10/15 = 5/R4. Solving gives R4 = 7.5Ω.
Correct Answer:
C
— 12.5Ω
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Q. If the resistances in a Wheatstone bridge are R1 = 10Ω, R2 = 15Ω, R3 = 5Ω, what should R4 be for the bridge to be balanced?
A.
7.5Ω
B.
10Ω
C.
12.5Ω
D.
15Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we find R4 = (R2 * R3) / R1 = (15 * 5) / 10 = 7.5Ω.
Correct Answer:
C
— 12.5Ω
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Q. If the resistances in a Wheatstone bridge are R1 = 10Ω, R2 = 20Ω, R3 = 15Ω, what should R4 be for the bridge to be balanced?
A.
30Ω
B.
15Ω
C.
20Ω
D.
10Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we find R4 = (R2 * R3) / R1 = (20 * 15) / 10 = 30Ω.
Correct Answer:
B
— 15Ω
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Q. If the resistances in a Wheatstone bridge are R1 = 10Ω, R2 = 20Ω, R3 = 15Ω, what is the value of R4 for the bridge to be balanced?
A.
30Ω
B.
20Ω
C.
15Ω
D.
10Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we find R4 = (R2 * R3) / R1 = (20 * 15) / 10 = 30Ω.
Correct Answer:
B
— 20Ω
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Q. If the resistances in a Wheatstone bridge are R1 = 20Ω, R2 = 30Ω, and R3 = 10Ω, what is the value of R4 for the bridge to be balanced?
A.
15Ω
B.
20Ω
C.
25Ω
D.
30Ω
Show solution
Solution
Using the balance condition R1/R2 = R3/R4, we have 20/30 = 10/x, solving gives x = 20Ω.
Correct Answer:
B
— 20Ω
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Q. If the resistances in a Wheatstone bridge are R1, R2, R3, and R4, what is the condition for balance?
A.
R1/R2 = R3/R4
B.
R1 + R2 = R3 + R4
C.
R1 * R4 = R2 * R3
D.
R1 - R2 = R3 - R4
Show solution
Solution
The condition for balance in a Wheatstone bridge is R1/R2 = R3/R4.
Correct Answer:
A
— R1/R2 = R3/R4
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Q. If the resistivity of a material is 1.5 x 10^-8 Ω·m, what is the resistance of a 3 m long wire with a cross-sectional area of 0.5 mm²?
A.
0.09 Ω
B.
0.18 Ω
C.
0.27 Ω
D.
0.36 Ω
Show solution
Solution
Resistance R = ρ(L/A) = (1.5 x 10^-8)(3)/(0.5 x 10^-6) = 0.09 Ω.
Correct Answer:
B
— 0.18 Ω
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Q. If the resistivity of a material is 2 x 10^-8 Ω·m and the wire has a length of 3 m and a cross-sectional area of 0.5 mm², what is the resistance?
A.
0.12 Ω
B.
0.15 Ω
C.
0.18 Ω
D.
0.20 Ω
Show solution
Solution
Resistance R = ρ * (L / A) = 2 x 10^-8 * (3 / 0.5 x 10^-6) = 0.12 Ω.
Correct Answer:
A
— 0.12 Ω
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Q. If the resistivity of a material is doubled, what happens to the resistance of a wire of fixed length and cross-sectional area?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
Resistance R is directly proportional to resistivity; if resistivity doubles, resistance also doubles.
Correct Answer:
A
— It doubles
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Q. If the resistivity of a material is doubled, what happens to the resistance of a wire of constant length and cross-sectional area?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
Resistance R is directly proportional to resistivity ρ, so if ρ is doubled, R also doubles.
Correct Answer:
A
— It doubles
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Q. If the resistivity of a material is halved, what happens to the resistance of a uniform wire of that material?
A.
Halved
B.
Doubled
C.
Remains the same
D.
Quadrupled
Show solution
Solution
Resistance is directly proportional to resistivity; halving resistivity halves the resistance.
Correct Answer:
A
— Halved
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Q. If the resistivity of a material is halved, what happens to the resistance of a wire of fixed length and cross-sectional area?
A.
Halved
B.
Doubled
C.
Remains the same
D.
Quadrupled
Show solution
Solution
Resistance is directly proportional to resistivity; halving resistivity halves the resistance.
Correct Answer:
A
— Halved
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Q. If the resistivity of a material is halved, what will happen to the resistance of a wire of fixed length and cross-sectional area?
A.
Halved
B.
Doubled
C.
Remains the same
D.
Quadrupled
Show solution
Solution
Resistance is directly proportional to resistivity; halving resistivity halves the resistance.
Correct Answer:
A
— Halved
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Q. If the resistivity of a superconductor is zero, what can be said about its resistance?
A.
Infinite
B.
Zero
C.
Depends on temperature
D.
Undefined
Show solution
Solution
A superconductor has zero resistivity, which means it has zero resistance.
Correct Answer:
B
— Zero
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Q. If the resistivity of copper is 1.68 x 10^-8 Ω·m, what is the resistance of a copper wire of length 100 m and diameter 1 mm?
A.
0.168 Ω
B.
0.168 kΩ
C.
1.68 Ω
D.
1.68 kΩ
Show solution
Solution
Resistance R = ρ * (L / A) = 1.68 x 10^-8 * (100 / (π * (0.5 x 10^-3)²)) = 0.168 Ω.
Correct Answer:
A
— 0.168 Ω
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Q. If the supply voltage in a Wheatstone bridge is increased, how does it affect the balance condition?
A.
It does not affect the balance condition
B.
It makes the bridge unbalanced
C.
It increases the current in the circuit
D.
It decreases the resistance
Show solution
Solution
Increasing the supply voltage does not affect the balance condition; it remains dependent on the resistance ratios.
Correct Answer:
A
— It does not affect the balance condition
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Q. If the temperature of a conductor increases, what happens to its resistivity?
A.
Increases
B.
Decreases
C.
Remains constant
D.
Depends on the material
Show solution
Solution
For most conductors, resistivity increases with temperature due to increased atomic vibrations.
Correct Answer:
A
— Increases
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Showing 181 to 210 of 607 (21 Pages)
Current Electricity MCQ & Objective Questions
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!
