Download summer holiday homework (2016-2017) class -xii physics

SUMMER HOLIDAY HOMEWORK (2016-2017)
CLASS -XII
PHYSICS
1. Draw a plot showing the variation of i) Electric field and ii) electric potential with distance
r due to a point charge Q.
2. Draw electric field lines for:
i)Charge q>0
ii) q<0
iii)Two equal and opposite charges.
iv)Two equal and similar charges.
3. State Gauss’ law in electrostatics. Find electric field due to infinitely charged long
straight uniformly charged wire of linear charge density 𝜆 at a given point using Gauss’
law. Draw ‘E’ vs distance.
4. Derive the expression for an electric field due to an electric dipole at a point on axial line
and on equatorial line.
5. Define relative permittivity. Why does water have very high dielectric constant?
6. Define electric dipole moment. Derive an expression for the total work done in rotating the
dipole through an angle in uniform electric field.
7. Derive a relation between drift velocity of electrons & resistivity.
8. Calculate the electric potential at a point P due to a charge of 4 x10-7 C located 9 cm away
from it.
9. A wire of resistance 20 ohm is stretched to double its original length. Calculate its
new resistance & resistivity.
10. Write an expression for the potential energy of two point charges q1 and q2 , separated by
distance r in an electric field E.
11. Draw the variation of resistivity with temperature for (i) Metals (ii) semiconductors and
(iii) alloys.
12. A charge q is enclosed by a spherical surface of radius ‘R’. If the radius is reduced
to half , how would the electric flux through the surface change.
13. Two fixed point charges +4e and +e are separated by a distance ‘a’, where should the
third point charge be placed for it to be in equilibrium.
14. Obtain the equivalent capacitance of the network in Fig. below. For a 300 V supply,
determine the charge and voltage across each capacitor.
15. Derive an expression for the capacitance of a parallel plate capacitor when the space
between the plates is filled with a dielectric.
16. Do any five Numericals on “Potentiometer and Kirchhoff’s” rule.
17. Do NCERT Exercise of chapter 2 and 3.