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A long metal bar of 30 cm length is aligned along a north south line and moves eastward at a speed of 10 ms-1. A uniform magnetic field of 4.0 T points vertically downwards. If the south end of the bar has a potential of 0V, the induced potential at the north end of the bar is
  • a)
    +12 V
  • b)
    -12 V
  • c)
    0 V
  • d)
    Cannot be determined since there is not closed circuit
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
A long metal bar of 30 cm length is aligned along a north south line a...
Understanding Induced Potential
When a conductor moves through a magnetic field, an electromotive force (emf) is induced across the length of the conductor due to electromagnetic induction.
Key Points to Consider:
- Length of the Bar: The metal bar is 30 cm long, which is equal to 0.3 m.
- Speed of the Bar: The bar moves at a speed of 10 m/s towards the east.
- Magnetic Field: A uniform magnetic field of 4.0 T points vertically downwards.
Direction of Induced Potential:
Using the right-hand rule for the motion of the conductor in the magnetic field:
- Thumb: Points in the direction of the velocity (east).
- Fingers: Point in the direction of the magnetic field (downwards).
- Palm: Indicates the direction of the induced current.
In this scenario, the induced current will flow from the north end to the south end of the bar.
Potential Difference Calculation:
The induced emf (E) can be calculated using the formula:
E = B * L * v
Where:
- B = Magnetic field strength (4.0 T)
- L = Length of the bar (0.3 m)
- v = Speed of the bar (10 m/s)
Calculating the induced emf:
E = 4.0 T * 0.3 m * 10 m/s = 12 V
Since the south end is at 0 V, the potential at the north end becomes:
- Potential at North End = 0 V + 12 V = 12 V
Conclusion:
Therefore, the induced potential at the north end of the bar is +12 V, making option 'A' the correct answer.
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Community Answer
A long metal bar of 30 cm length is aligned along a north south line a...
Induced emf = Blv = 12V. It is induced in the northward direction by right hand rule (emf=)
therefore if the south end of the pole has potential of 0V, the north end will have a potential of 12V.
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A long metal bar of 30 cm length is aligned along a north south line and moves eastward at a speed of 10 ms-1. A uniform magnetic field of 4.0 T points vertically downwards. If the south end of the bar has a potential of 0V, the induced potential at the north end of the bar isa)+12 Vb)-12 Vc)0 Vd)Cannot be determined since there is not closed circuitCorrect answer is option 'A'. Can you explain this answer? for Class 12 2025 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about A long metal bar of 30 cm length is aligned along a north south line and moves eastward at a speed of 10 ms-1. A uniform magnetic field of 4.0 T points vertically downwards. If the south end of the bar has a potential of 0V, the induced potential at the north end of the bar isa)+12 Vb)-12 Vc)0 Vd)Cannot be determined since there is not closed circuitCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Class 12 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A long metal bar of 30 cm length is aligned along a north south line and moves eastward at a speed of 10 ms-1. A uniform magnetic field of 4.0 T points vertically downwards. If the south end of the bar has a potential of 0V, the induced potential at the north end of the bar isa)+12 Vb)-12 Vc)0 Vd)Cannot be determined since there is not closed circuitCorrect answer is option 'A'. Can you explain this answer?.
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