1. Draw schematically an equipotential
surface of a uniform electrostatic field along x-axis.
2. Sketch field lines due to (i) two equal
positive charges near each other (ii) a dipole.
3. Name the physical quantity whose SI unit is
volt/meter. Is it a scalar ora vector quantity?
4. Two point charges repel each other with a
force F when placed in water of dielectric constant 81.
What
will the force between them when placed the same distance apart in air?
5. Electric dipole moment of CuSO4 molecule
is 3.2 × 10–32 Cm. Find theseparation between copper
and
sulphate ions.
6. Net capacitance of three identical
capacitors connected in parallel is 12microfarad. What will be
the
net capacitance when two of them areconnected in (i) parallel (ii) series?
7. A charge q is placed at the centre of an
imaginary spherical surface. What will be the electric flux
due
to this charge through any half of the sphere.
8. Draw the electric field vs distance (from
the centre) graph for (i) a long charged rod having linear
charge
density λ <; 0 (ii) spherical shell of radius R and charge Q > 0.
9. Diagrammatically represent the position of
a dipole in (i) stable (ii) unstable equilibrium
when
placed
in a uniform electric field.
10. A charge Q is distributed over a metal
sphere of radius R. What is the electric field and electric
potential
at the centre?
11. If a body contains n1 electrons and n2 protons
then what is the total charge on the body?
12. What is the total positive or negative
charge present in 1 molecule of water.
13. How does the energy of dipole change when
it in rotated from unstable equilibrium to stable equilibrium in a uniform
electric field.
14. Write the ratio of electric field
intensity due to a dipole at a point on the equatorial line to the field
at a
point at a point on the axial line, when the points are at the same distance
from the centre of
dipole.
15. Draw equipotential surface for a dipole.
16. An uncharged conductor A placed on an
insulating stand is brought near a charged insulated conductor B. What happens
to the charge and potential of B?
17. A point charge Q is placed at point O
shown in Fig. Is the potentialdifference VA – VB positive,
negative
or zero, if Q is (i) positive (ii) negative charge.
18. An electron and proton are released from
rest in a uniform electrostatic field. Which of them will
have
larger acceleration?
19. In an uniform electric field of strength
E, a charged particle Q moves point A to point B in the
direction
of the field and back from B to A. Calculate the ratio of the work done by the
electric
field in taking the charge particle from A to B and from B to A.
field in taking the charge particle from A to B and from B to A.
20. If a dipole of charge 2μC is placed
inside a sphere of radius 2m, what is the net flux linked with
the
sphere.
21. Four charges + q, –q, +q, –q are placed
as shown in the figure. What is the work done in
bringing
a test charge from ∞ to point 0.
22. Calculate number of electric field lines
orignating from one coulomb charge.
23. If the metallic conductor shown in the
figure is continuously charged from which of the points
A,B,C
or D does the charge leak first. Justify.
24. What is dielectric strength? Write the
value of dielectric strength of air.
25. Two charge –q and +q are located at
points A (0, 0, –a) and B(0, 0, +a). How much work is done
in
moving a test charge from point (b, 0, 0) to Q (–b, 0, 0)?
26. If an electron is accelerated by a
Potential difference of 1 Volt, Calculate the gain in energy in
Joule
and electron volt.
27. Draw schematically the equipotential
surface corresponding to a field that uniformly increases in
magnitude
but remains in a constant (say z) direction.
28. Without referring to the formula C = ε0A/d.
Explain why the capacitance of a parallel plate
capacitor
reduces on increasing the separation between the plates?
29.Draw field lines to show the position of
null point for two charges + Q1 and –Q2 when magnitude
of Q1
> Q2 and mark the position of null point.
30. How does the relaxation time of electron
in the conductor change when temperature of the conductor decreases.
31. Sketch a graph showing variation of
resistivity with temperature of (i) Copper (ii) Carbon.
32. The emf of the driver cell (Auxillary
battery) in the potentiometer experiment should be greater than emf of the cell
to be determined. Why?
34. You are required to select a carbon
resistor of resistance 47kΩ ± 10% from a large collection. What should be the
sequence of color bands used to code it?
36. Two wire one of copper and other of
manganin have same resistance and equal
length. Which wire is thicker?
37.Why is the potentiometer preferred to a
voltmeter for measuring emf of a cell?
38. How can a given 4 wires potentiometer be
made more sensitive?
39. Why is copper not used for making
potentiometer wires?
40. A copper wire of resistance R is
uniformally stretched till its length is increased to n times its original
length. What will be its new resistance?
41. What is the largest voltage that can be
safely put across a resistor marked 196Ω, 1W?
42. When does the terminal voltage of a cell
become (i) greater than its emf (ii) less than its emf?
43.A car battery is of 12V. Eight dry cells
of 1.5 V connected in series also give 12V, but such a
combination
is not used to start a car. Why?
44. Two electric lamps A and B marked 220V,
100W and 220V, 60W respectively. Which of the two
lamps
has higher resistance?
45. Resistors of high value are made up of
carbon. Why ?
46. A 16Ω thick wire is stretched so that its
length becomes two times.Assuming there is no change in density on
stretching. Calculate the resistance of new wire.
47. State the Condition under which the
terminal potential difference across
a battery and its emf are equal.
48. State the Condition for maximum current
to be drawn from a Cell.
