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As the CBSE Class 12 board exams get closer, it’s important for students to understand the new exam pattern. Starting in the 2024-25 school year, CBSE will include 50% more competency-based questions. These questions will be both multiple choice and written, focusing on how to use what students have learned in real-life situations.
For Class 12 Physics, Unit -3 on Magnetic Effect of Current & Electricity, CBSE has provided competency-based questions that help improve understanding and application skills. It highlights key competency-based questions and provides answers to help students succeed. These questions are designed to help students strengthen their understanding and apply concepts effectively for their exams.
By practicing these competency-based questions, students will get familiar with the types of questions they are likely to face in the exam. The free PDF includes a variety of questions, such as multiple-choice (MCQs) and free-response questions, with answers provided to guide students in their preparation.
CBSE Class 12 Physics Chapter 3: Magnetic Effect of Current & Electricity Important Competency-Based Questions
Q.1 Read the following points of comparison between electric and magnetic fields carefully.
i. Both Coulomb’s law and Biot‐ Savart’s laws follow inverse square law.
ii. Both electric and magnetic field values depend upon the angle between the displacement vector and the field source.
iii. Electric field is produced by a scalar source whereas magnetic field is produced by a vector source.
iv. The direction of the magnetic field is along the displacement vector joining the field source and field point. On the other hand, the electric field is perpendicular to the plane containing the displacement vector joining the field source and the field point.
Identify the correct statements.
A. only i and ii
B. only iii and iv
C. only ii and iv
D. only i and iii
Answer. D. only i and iii
Q.2 A deuteron and an alpha particle move with the same kinetic energy under the effect of identical magnetic fields.
What will be the ratio of the radii of their paths followed?
A. 1
B. √2
C. 1/2
D. 2
Answer. B. √2
Q.3 A particle of charge q and mass m projected with a speed v into a uniform magnetic field B undergoes circular motion under the effect of magnetic force.
Identify an INCORRECT statement.
A. Both KE and PE of this charged particle remain constant. So no work is done by the magnetic field on it.
B. An identical charged particle projected at an angle other than 90o with magnetic field B will undergo helical motion.
C. Another charged particle of a different specific charge, projected with the same speed will still have the same angular frequency.
D. An identical charged particle projected with double the speed in the same magnetic field will follow a circular path of larger circumference than the earlier one but with the same time period.
Answer. C. Another charged particle of a different specific charge, projected with the same speed will still have the same angular frequency.
| Download PDF | |
| CBSE Class 12 Physics Unit 1 Electrostatics : Important Competency-Based Questions 2024-25 | Click Here |
| CBSE Class 12 Physics Unit 2 Current Electricity : Important Competency-Based Questions 2024-25 | Click Here |
| CBSE Class 12 Physics Unit 3 Magnetic Effect of Current and Electricity : Important Competency-Based Questions 2024-25 | Click Here |
| CBSE Class 12 Physics Unit 4 Electromagnetic Induction and Alternating Current (AC) : Important Competency-Based Questions 2024-25 | Click Here |
Q.4 A negatively charged particle moves with velocity v through a magnetic field B and experiences a magnetic force F.
In each of the diagrams below, the representation of magnetic field lines is missing.
Identify the probable direction of magnetic field lines in each case as Left, Right, Upwards or Downwards.
A. i‐Right, ii‐Upwards, iii‐Upwards, iv‐Right
B. i‐Left, ii‐Downwards, iii‐Downwards, iv‐Left
C. i‐Downwards, ii‐Right, iii‐Upwards, iv‐Upwards
D. i‐Left, ii‐Right, iii‐Upwards, iv‐ Downwards
Answer. B. i‐Left, ii‐Downwards, iii‐Downwards, iv‐Left
Q.5 Each of the diagrams represents magnetic field lines around a wire
carrying current I from different perspectives.
Identify which of the following representations are correct.
A. only i and iv
B. only ii and iii
C. only i and iii
D. only ii and iv
Answer. A. only i and iv
Q.6 A rod of insulating material of length 0.5 m carries a static charge of 1 C at one end. The rod is rotated in a vertical plane about a horizontal axis passing through the other end with an angular frequency of 10π rad/s.
What is the magnetic field at the center of the circular path?
A. 2π x 10‐6 T
B. 4π2 x 10‐6 T
C. 0.4 x 10‐7 T
D. Zero
Answer. A. 2π x 10‐6 T
Q.7 A wire of length L carrying a current I can be turned into a circular coil of N turns. For what turned value of N, will the magnetic moment of this current carrying coil be maximum?
A. one
B. 4πL
C. infinite
D. (Magnetic moment is a constant for a given L and is independent of N)
Answer. A. one
Q.8 Which of the following statements is INCORRECT for a magnetic dipole?
A. A freely suspended magnetic dipole in a uniform magnetic field always turns to align parallel to the external magnetic field.
B. A magnetic dipole that is free to move in a non‐uniform magnetic field can slide as well as rotate.
C. The torque required to hold&nb...
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👉 Read Also - CBSE Class 12 Half-Yearly/Mid Term 2024-25 : Most Important Questions with Answers; PDF Download (All Subjects)
👉 Read Also - How CBSE’s New Exam Pattern Will Impact Class 11 and 12 Students
👉 CBSE Class 12 Study Materials
| CBSE Class 12 Syllabus 2024-25 | CBSE Class 12 Previous Year Papers |
| NCERT Books For Class 12 Books | NCERT Class 12 Solutions |
| CBSE Class 12 Full Study Material | CBSE Class 12 Sample Paper 2024-25 |
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