Two Marks Questions with Answers

Two Marks Questions with Answers

Q.1 Obtain Poisson's equation from Gauss's law.

(Refer section 6.2.)

Q.2 Express Laplace's equation in different co-ordinate systems.

AU : Dec.-02, 03, 04, May-06

Ans. : Laplace's equation in different co-ordinate systems is,

Q.3 State the difference between Poisson's equation and Laplace's equation.

AU : Dec.-10, 14, May-19

Ans. : The Poisson's equation is given by,

If in a certain region, volume charge density is zero (ρv = 0), which is true for dielectric medium then the Poisson's equation takes the form,

... (For charge free region)

This is special case of Poisson's equation and is called Laplace's equation.

Q.4 Write Laplace equation and its applications.

AU : Dec.-05

Ans. : The Laplace's equation is given by,

... (For charge free region)

It can be used to find electric field intensity in an electron beams, to solve problems related with an electron gun, obtaining the capacitance under different conditions, to obtain potential at a point under different situations etc.

Q.5 State Uniqueness theorem.

Ans. : The Uniqueness theorem can be stated as :

If the solution of Laplace's equation satisfies the boundary condition then that solution is unique, by whatever method it is obtained.

The solution of Laplace's equation gives the field which is unique, satisfying the same boundary conditions, in a given region.

Q.6 Write down Laplace's and Poisson's equation.

AU : May-10, 11, 14, Dec.-10, 17

Ans. :

Q.7 Write Poisson's equation in cylindrical co-ordinates.

AU : May-16

Ans. :