TEACHERS SECTION

ELECTROSTATICS TEST PAPER FOR CLASS XII

1. What orientation of an electric dipole in a uniform electric field corresponds to its stable equilibrium?

2. What is the area of the plates of a parallel plate capacitor of capacitance 2F and with separation between plates 0.5 cm?

3. What is the work done in carrying a point charge 10 nC between two points separated by a distance 5 cm on an equipotential surface?

4. A parallel plate capacitor is made by stacking ‘n’ equally spaced plates connected alternatively. If the capacitance between any two plates is ‘C’, determine the resultant capacitance of the combination

5. Calculate the coulomb force between two a particles separated by a distance of 3.2 x 10^-15 m

6. Draw graph showing variation of electric field with distance for a uniformly charged metallic sphere.

7. An electron and proton are free to move in an electric field. Which one will have greater acceleration? Why?

8. Sketch two equipotential surfaces for (a) a point charge. (b) between two plane sheets of charge.

9. Show that the work done in rotating an electric dipole of dipole moment p in a uniform electric field E by an angle θ from the equilibrium postition W = PE(1-cos θ)

10. The given graph shows the variation of charge ‘q’ verses potential difference for two capacitors C1 and C2 .The capacitors have same plate separation, but the plate area of C2 is double that of C1.Identify the line in the graph corresponding to C1 & C2 and why?

11. Derive an expression for the torque acting on an electric dipole placed in a uniform electric field.

12. Derive an expression for the capacitance of a parallel plate capacitor.

13. You are given three capacitors of value 2μF, 3μF, 6μF. How will you connect them to a resultant capacity of 4μF?

14. Two equally charged identical metal spheres A and B repel each other with a force of 2·0 x 10^-5 N. Another identical uncharged sphere C is touched to A and then placed at the mid point between A and B. What is the net force on C?

15. A dielectric slab of thickness t introduced between the plates of a parallel plate capacitor separated by a distance d. (t < d). Derive an expression for the capacitance of the capacitor

16. Describe the principle construction and working of a Van de graff Generator with the help of a neat labeled diagram.

17. Use Gauss theorem to derive an expression for the electric field at a point due to

a. an infinite plane sheet of charge of uniform charge density σ

b. a thin infinitely long straight line  of charge of uniform charge density λ

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Some inspiring words and quotes for teachers

“Teachers are the chosen best of humanity”

“We Know everything past and present and probably the future too, but we don’t know that we know every thing. It requires a teacher to help us unveil the knowledge hidden in ourselves”

“Learning fills a person with joy”

A child (or any one ) becomes happy when he/she learns a new thing and when he learns something new, he practices it several times until he masters the new knowledge. Therefore a teacher has to help the students become curious to know more so that the student is supplied with the information which he wants.”

“A teacher evokes the inner teacher inside the taught”

TEACHER AS FACILITATOR

Taking another step towards reforming the education system by making it more student-centric, the Central Board of Secondary Education has “advised” teachers in affiliated schools to act more as facilitators than instructors by cutting down on teacher-talking time and instead enabling more peer-group learning.
In a recent set of guidelines spelling out, in no uncertain terms, the curriculum to be followed in Classes IX and X in CBSE schools, the board has asked teachers “to reduce teacher-talking time to the minimum; encourage classroom interaction among peers, students and teachers; take up questions for discussion to encourage pupils to participate, and to marshal their ideas and express and defend their views.”

Academics say it is important that teachers speak less in class in order to adopt a constructive approach towards a student’s learning and development. “The child must discover things for itself. Unfortunately, in our country teacher training schools still advocate the teacher talk method. Such guidelines will allow the teacher to look at other teaching methodologies, some of which have been prescribed,” says Neera Chopra, an educational consultant based in Delhi who has worked with several schools in Delhi and abroad, and is an expert on the continuous and comprehensive evaluation suggested by the CBSE in all affiliated schools.

“In the schools that I visit, I often come across children who say they are able to understand 60% from the textbooks, and that teachers make the whole learning experience boring by trying to explain things to them. Instead, teachers should focus on guiding children to the right places to look for information, not by explaining everything in textbooks,” she says.

While the guidelines break several barriers by making rote learning infeasible and instead focussing on learning by doing, there are fears that such precise instructions could stifle a teacher’s spontaneity and tendency to innovate in the classroom.

A facilitator makes learning happen by demystifying the process of learning and making students autonomous learners.

It is believed by many educators now that facilitation is a never ending function of a teacher who continually develops and supports the learning potential of students.

As a teacher, what is your opinion? Let’s interact and discuss. Post your comments and ideas.