7/31/2019 01A Electrostatics, Electric Field, Dipoles

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ASSIGNMENT 1:ELECTROSTATICS,ELECTRIC FIELDS,DIPOLES

1. State and explain the properties of charges.2. What is Induction? How do you charge a conductor by induction?3. State and explain Coulombs Law in Vector notation [Favourite ISC question]4. What is permittivity of free space and relative permittivity? What is the relation between the two? How does it

affect the force between two charges? Illustrate using an example.

5. Compare and contrast between Electrostatic and Gravitational Forces.6. State and explain the principle of superposition.7. In dealing with the idea of Electric Fields, explain the difference between Source charge(s) and a test charge.

What sign would you associate with a test charge and why?

8. What is an Electric Field (E)? How do we measure the E at any given point?9. What are the different ways of representing an E? Which is the most widely used representation and why?10.How do you find (qualitatively) the difference in magnitude ofE at two places in an E configuration represented

by Field Lines?

11.State and explain the properties of Electric Field Lines.12.What is a dipole? Show that the E around a dipole falls of as

instead as

both equatorially and axially. How do

you think the E due to a uniformly charged infinitely thin long straight conductor falls? Can you prove it ?

13.Study the variation of y with x for the following relations. Use a graph and plot values. Also use the softwareMicrosoft Math to learn how one changes when the other changes.

(i) (ii) (iii)

(iv)

(v)

(vi)

(vii)

(viii)

Remember that in all our discussions y and x will be E and r or V and r, etc.

14.What do you mean by (i) Linear charge density (ii) Surface charge density and (iii) Volumecharge Density?

15.Derive the Eat any point P on the axis of a uniformly charged ring of radius and hence find the E at the centreof the ring.

16.A positively charged ball hanging from a string is brought near a non-conducting object. The ball is attracted tothe object. From this experiment, is it possible to infer that the object is negative? Why?

17.A very small uncharged metallic coated pith ball (very light) is suspended in the region between two vertical metalplates in which a uniform E occurs. If the two plates are charged one positive and one negative, describe the

motion of the ball after it is brought into contact with one of the plates. If the ball is heavier, how does the motion

of the ball change?

18.A test charge of +3C is at a point P where the E due to certain source charges is directed to the right and has amagnitude of . If the test charge is replaced with a10nC charge at the same point, what happens to

the E due to the source charges at the point P?

19.Calculate the E at the centre of a cube of side a due to charges +10C each on its vertices? Calculate themagnitude and direction ofE if half the charges are removed all from one side?

20.Two charges +10C and +7C are separated by a distance of 9cm. Show at which point on the line joining the twocharges is the electric field . Does this position of change if (i) the polarity of one of the charges is

changed? (ii) If the Polarity of both the charges are changed? If in any of the two cases it does change, find the

new position of the point where .