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(Code-I015/12P2)
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QUESTION PAPER
CLASS-XII (Code-I015/12P2)
Time : 3 Hrs
Topic : Electrostatic
Student’s Name:………………….
Max. Marks : 70
Date : ……………………..
SID NO:……….…...
GENERAL INSTRUCTIONS:
1.
Answer to this Paper must be written on the Answer Copy.
2.
You will not be allowed to write during the first 05 minute. This time is to be spent in reading the
Question Paper.
3.
The time given at the head of this paper is the time allowed for writing the answer.
12. Name the physical quantity which has its unit
Section –A (1 Mark each)
(Attempt all questions)
joule coulomb−1. Is it a scalar or vector?
13. What is the potential due to a point charge?
1. Distinguish
between
a
dielectric
and
a
14. The safest way to protect yourself from lighting
conductor?
is to be inside a car. Comment.
2.
What is electric charge?
3.
Can a body has charge 1.5 e, where e is the
15. What is a net charge on a charge capacitor?
16. What is the order of capacitances used in
electronic charge?
power supplies?
4.
A body has excess of electrons what does it
imply?
Section –B (2 Mark each)
(Attempt all questions)
5. What is the value of charge on electron? Is a
charge less than this value possible?
6.
Electric charge is additive in nature, explain?
7.
What is the basic cause
of quantization of
9.
weather. Explain, why?
18. Can a charged body attract another uncharged
charge?
8.
17. Automobile ignition failure occurs in damp
Quarks are the building blocks of nucleons and
body? Explain.
possess fractional electronic charge. Dos this
19. Can ever the whole excess charge of a body be
discover violate the principle of quantization of
transferred to the other? If yes, how and if not
charge?
why?
What do electric lines of force represent?
10. Why two electric lines of force cannot intersect
20. How many electrons must be removed from a
ball of mass 3.2 g so that it may float in an
electric field of intensity 1010 N/C directed
each other?
11. Why there is no work done in moving a charge
from one point to another on an equipotential
upwards?
21. Define relative permittivity of a medium.
surface?
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22. Two points charges +Q and +4Q are separated
by a distance of 6a. Find the point on the line
Section –C (3 Mark each)
(Attempt all questions)
joining the two charges where the electric field
31. The opposite corners of a square
charge each and the other two opposite corners
is zero?
23. The electric
potential
at 0.1 m from a point
charge is +50V. What is the magnitude
and
three
equipotential
surfaces
corresponding to a field that uniformly increases
in magnitude
of the same square carry q charge each. If the
resultant force on q is zero, how are Q and q
related?
sign of the charge?
24. Draw
carry Q
but remains constant along Z-
32. A spherical conductor of radius 12 cm has a
charge of 1.6 ×10−7C distributed uniformly on its
surface. What is the electric field.
direction. How are these surfaces different from
(i)
Inside the sphere?
that of a constant electric field along z-direction?
(ii)
Just outside the sphere?
25. The kinetic energy of a charged particle
(iii) at a point 18 cm from the centre of the
sphere?
decreases by 10J as it moves from a point at
potential 100 V to a point at potential 400 V.
Find the charge on the particle.
Section –D (15Mark each)
(Attempt any four questions)
26. Work done in moving a test charge between two
points in an electric field is independent of the
path followed. Comment.
27. How does an electrically polarized object differ
from an electrically charged object?
each. They coalesce to form a bigger drop.
Calculate the potential of bigger drop.
29. A number of spherical conductors of different
radii have same potential. How does the surface
charge density on them relate to radius?
30. A small particle carrying a negative charge
1.6
×10
C
is
suspended
in
and qD=−5μC are located at the corners of a
square ABCD of side 10 cm. What is the force
on a charge of 1μC placed at the centre of the
28. 27 drops of same size are charged at 220 V
−19
33. Four point charges qA=2μC, qB=−5μC, qC=2μC
equilibrium
between the horizontal metal plates 5 cm apart,
square?
34. Given figure shows a charge array known as an
electric quadrupole. For a point on the axis of
the quadrupole, obtain the dependence of
potential on r for r/a>>1 and contrast your
results with that due to an electric dipole and an
electric monopole (i.e., a single charge)
A
q
a
B
−q –q
having potential difference of 3000 V across
a
C
q
q
r
them, find the mass of the particle.
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35. Geeta has dry hair. A comb ran through her dry
37.
hair attract small bits of paper. She observes
that Neeta with oily hair combs her hair; the
comb could not attract small bits of paper. She
consults her teacher for this and gets the
answer. She then goes
and
shows
this
to the junior classes
phenomenon
as
physics
experiment to them. All the juniors feel very
happy and tell her that they will also took for
such interesting things in nature and try to find
the answer. She succeeds in forming a science
club in her school.
Read the above passage and answer the
following question.
(i)
38.
In Pradeep’s classroom the fan was running
very slowly. Due to which his teacher was
sweating and was restless and tired. All his
classmates wanted to rectify this. They called
an electrician who came and change the
capacitor only after which the fan started
running fast.
(i)
What energy is stored in the capacitor
and where?
(ii)
What values did the classmate have?
A man travelling in a car during heavy rain
and thunderstorm sees a boy standing under
a tree. He immediately stops his car and asks
the boy to get inside the car and saves him
from a possible natural calamity. Answer the
following questions based on the above
information.
(i)
What danger did the boy had while
standing under the tree during the
thunderstorm?
(ii)
How is it safer inside the car during such
weather?
(iii)
What according to you are the values
displayed by the man to help the boy?
(iv)
Give another example from everyday
life situation which represent display of
similar values.
What according to you are the values
displayed Geeta?
(ii) Explain the phenomenon involved.
36. Four points charges +1μC, +1μC, −1μC and
−1μC are placed at the corners A, B, C, D of a
square of each side 0.1 m.
(i)
Calculate electric potential at the centre 0 of
the square.
(ii)
If E is middle point of BC, what is the work
done in carrying an electron from 0 to E?
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Examination Superintendent
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Branches : Indira Nagar, Gomti Nagar, Hazratganj
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