CBSE 12th Exams Start in a Week: Check CBSE 12th Physics Chapter 1 Important Questions

CBSE 12th Physics Chapter 1 Important Questions: The Central Board of Secondary Education (CBSE), India, will conduct the class 12 Board exams between Feb 15 to Apr 5, 2023. The Physics exam is scheduled for Mar 6. Students completing their CBSE 12th Physics Revision must thoroughly study the first chapter, i.e., Electric Charges & Fields. Continue reading further to check the CBSE 12th Physics Chapter 1 Important Questions and their solutions.

Also Read: CBSE 12th Exams Begin in 8 Days: Check CBSE 12th Physics Chapter 2 Important Questions

CBSE 12th Physics Chapter 1 Important Questions & Solutions

Students can find the CBSE 12th Physics Important Questions and solutions for the first Chapter (Electric Charges & Fields) below.

Question 1) In which orientation a dipole placed in a uniform electric field is in stable, unstable equilibrium?

Answer: A dipole is placed parallel to the electric field for stable equilibrium. For unstable equilibrium, a dipole is placed antiparallel to the electric field.

Question 2) Name the physical quantity whose S.I. unit is JC-1. Is it a scalar or a vector quantity?

Answer: Physical quantity whose S.I. unit is JC-1 is Electric potential. It is a Scalar quantity.

Question 3) Why should the electrostatic field be zero inside a conductor?

Answer: Electrostatic field inside a conductor should be zero because of the absence of charge. As in a static condition, the charge remains only on the surface.

Question 4) Why must the electrostatic field be normal to the surface at every point of a charged conductor?

Answer: So that tangent on charged conductor gives the direction of the electric field at that point.

Question 5) What is the direction of the electric field at the surface of a charged conductor having charge density σ < 0?

Answer: The direction of an electric field is normal and inward to the surface.

Question 6) Why do the electric field lines not form closed loops?

Answer: Electric field lines do not form closed loops because the direction of an electric field is from positive to negative charge. So one can regard a line of force starting from a positive charge and ending on a negative charge. This indicates that electric field lines do not form closed loops.

Question 7) Is the electric field due to a charge configuration with a total charge of zero necessarily zero? Justify.

Answer: No, it is not necessarily zero. If the electric field due to a charge configuration with total charge is zero because the electric field due to an electric dipole is non-zero.

Question 8) Why do the electrostatic field lines not form closed loops?

Answer: Electric field lines do not form closed loops because the direction of an electric field is from positive to negative charge. So one can regard a line of force starting from a positive charge and ending on a negative charge. This indicates that electric field lines do not form closed loops.

Question 9) Why do the electric field lines never cross each other?

Answer: The electric lines of force give the direction of the electric field. In case two lines of force intersect, there will be two directions of the electric field at the point of intersection, which is impossible.

Question 10) What is the electric flux through a cube of side 1 cm which encloses an electric dipole?

Answer: Zero because the net charge of an electric dipole (+ q and – q) is zero.

Question 11) Why are electric field lines perpendicular at a point on an equipotential surface of a conductor?

Answer: If the electric field lines were not normal to the equipotential surface, they would have a non-zero component along the surface. To move a unit test charge against the direction of the component of the field, work would have to be done, which means this surface cannot be equipotential. Hence, electric field lines are perpendicular at a point on an equipotential surface of a conductor.

Question 12) How does the electric flux due to a point charge enclosed by a spherical Gaussian surface get affected when its radius is increased?

Answer: The electric flux due to a point charge enclosed by a spherical gaussian surface remains 'unaffected' when its radius is increased.

Question 13) Does the charge given to a metallic sphere depend on whether it is hollow or solid? Give a reason for your answer.

Answer: No, it does not because the charge resides only on the conductor's surface.

Students must pay attention to these CBSE 12th Physics Chapter 1 Important Questions as there is a high possibility that a few might come for the Board Exam.

Also Read: CBSE 12th Exams to Held Feb 15 Onwards: Check CBSE 12th Physics Chapter 3 Important Questions