Class 12 Question Paper 2022-23 Physics (Half Yearly)

HALF YEARLY EXAMINATION

Question Paper
2022-23

NCERT BASED SYLLABUS
FOR CBSE AND STATE BOARD
FOLLOWING NCERT

QUESTION PAPER
PT-
PT-2/HALF YEARLY EXAMINATION, 2022-
2022-23
PHYSICS
Time – 3 Hours Class - XII M.M. - 70
Date – 16.09.2022 (Friday)
Name of the student _________________________________________________ Section _____

General Instructions –
• There are 34 questions in all. All questions are compulsory.
• This question paper has five sections: Section A, Section B, Section C, Section D
and Section E.
• Section A contains sixteen questions of one mark each,
o Section B contains 1 case study question of four mark,
o Section C contains seven questions of two marks each,
o Section D contains seven questions of three marks each,
o Section E contains three questions of Five marks each,
• There is no overall choice. However, internal choice has been provided in one
question of two marks, one question of three marks and in all questions of five
marks. You have to attempt only one of the choices in such questions.

SECTION - A
Q.1 Two large, thin metal plates are parallel and close to each other. On their inner faces,
the plates have surface charge densities of opposite signs and of magnitude 17.0 × 10–22
C/m2. What is the Electric field in the outer region of the first plate?
A) 1.92 × 10–10 N/C B) 0.96 × 10–10 N/C C) 0.48 × 10–10 N/C D) zero
Q.2 An arbitrary surface encloses a dipole (q and –q charge separated by a small distance).
What is the electric flux through this surface?




A) B) C) D) zero
  

Q.3 Which statement is not correct for an equipotential surface?
A) Electric field is always perpendicular to the equipotential surface.
B) Potential difference between any two points on it is zero.
C) Equipotential surfaces are always spherical in shape.
D) No work is required to move a charge on an equipotential surface.
Q.4 Assume that an electric field ⃗ = 30 ̂ exists in space. Then the potential difference
VA − VO, where VO is the potential at the origin and VA the potential at x = 2 m is:

A) + 60 V B) − 60 V C) + 120 V D) −120 V
Q.5 We know that charge in a capacitor is given as Q = CV. Which of the following
relation/statement regarding C is correct?
A) C ∝


B) C ∝ Q

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C) depends on geometrical factors like area of the plates and separation between them.
D) C does not depend on the medium between the plates of the capacitor.
Q.6 If an electron is moving in the positive X
X-direction,
direction, in a region where uniform magnetic
field is applied along positive Y
Y-direction,
direction, then what will be the direction of the
magnetic force?
A) Along the positive Z-direction.
direction. B) Along the negative Z
Z-direction.
C) Along the positive Y-direction.
direction. D) Along the negative Y
Y-direction.
Q.7 There is one circular loop of a uniform wire whose radius is R. Electric current I enters
at one point on its circumference and leaves at a diametrically opposite point. What
will be the net magnetic field intensity at the centre of the loop?
µ µ µ
A)   B)   C)   D) Zero
  

Q.8 There is a uniform magnetic field and a charged particle is given an initial velocity at
an acute angle to the direction of the magnetic field. What kind of path will the particle
follow?
A) Circle B) Straight line
C) Helical path with a non-uniform
uniform pitch. D) Helical path with a uniform pitch.
Q.9 The angle of dip at a place where the horizontal and vertical components of Earth’s
magnetic field are equal is:
A) 45° B) 30° C) 0° D) 60°
Q.10 Electromagnets are made of soft iron because soft iron has
A) Low retentivity and low coercive force B) High retentivity and low coercive force
C) Low retentivity and high coercive force D) High retentivity and high coercive force
Q.11 Metallic rectangular loop of wire of size L × b is moved in its plane inside uniform
magnetic field B as shown in figure.

R is the resistance of loop and v is its speed. Induced current in the loop is
A) BLv/R , clockwise B) 2BLv/R, anticlockwise C) 2Bbv/R ,clockwise D) zero
Q.12 In Lenz’s law there is conservation of
A) charge B) momentum C) energy D) None of these

Q.13 The magnetic field in a travelling electromagnetic wave has a peak value of 20 nT. The
peak value of electric field strength is :
A) 3 V/m B) 6 V/m C) 9 V/m D) 12 V/m
Directions (for Q. No. 14 to 16) : These questions consist of two statements, each
printed
rinted as Assertion and Reason. While answering these questions, you are required to
choose any one of the following four responses.

(a) Both Assertion and Reason are correct and the Reason is a correct explanation of
the Assertion.
(b) Both Assertion and Reason are correct but Reason is not a correct explanation of the
Assertion.
(c) Assertion is correct, Reason is incorrect
(d) Both Assertion and Reason are correct.
Q.14 Assertion: Electric lines of field cross each other.
Reason: Electric field at a point superimposes to give one resultant electric field.
Q.15 Assertion: The strength of the magnetic field produced at the centre of a current
carrying circular coil increases on increasing the number of turns of the circular coil.
Reason : Magnetic field strength is directly proportional to the number of turns of the
circular coil.
Q.16 Assertion: The electromagnetic wave is transverse in nature.
Reason: Electromagnetic wave propagates parallel to the direction of electric and
magnetic fields.
SECTION - B
Q.17 Read the following passage and answer the following questions:
Resistance is the property of the conductor which opposes the free flow of electric
current or electron. Resistance can also be simplified as the ratio of the voltage applied
to the electric current flowing through it. The resistance of a conductor generally
depends on a number of factors: length, nature of the material, and the area of cross-
section. For a conductor material, the resistance of the material is inversely
proportional to the area of cross-section and directly proportional to the length of the
conductor. Resistivity is a property of a conductor which is defined as the resistance
offered by a material per unit length for a unit cross-section. Relation between

Resistivity and Resistance is: R = , where ρ is the resistivity, l is the length of the

conductor and A is the cross-sectional area.
(I) Resistivity of a conductor depends upon
A) its material B) its cross-sectional area
C) its length D) All of the above
(II) Consider a thin square sheet of side L and thickness t, made of a material of
resistivity ρ.

The resistance between two opposite faces, shown by the shaded areas in the figure is:
A) directly proportional to L B) directly proportional to t
C) independent of L D) independent of t

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(III) With increase in temperature, the resistivity of a conductor
A) increases B) decreases
C) may increase or decrease D) does not change
(IV) Which of the following quantities does not change when a resistor is heated by
passing current through it?
A) Resistance B) Resistivity C) Drift velocity D) Number of free electrons
SECTION - C
Q.18 Consider a uniform electric field  ⃗ = 3 × 103 ̂ N/C ,What is the flux of the field through
a square of side 10 cm, if its plane makes a 60° angle with X-axis?
X
Q.19 Two capacitors C1 and C2 have the same separation between the plates but the plate
area of C2 is twice that of C1. The given graph shows the variation of q with V.

Which of the two lines in the graph represents C1 and why?
OR
Eight identical drops merge to form a bigger drop. If the potential of each drop is 220 V,
find the potential of the bigger drop.
Q.20 Write any two factors on which internal resistance of a cell depends.
Q.21 The figure shows three infinitely long straight parallel current carrying conductors.

Find the magnitude and direction of the net magnetic field at point A lying on
conductor 1.
Q.22. What is motional electromotive force? Write an expression for it.
Q.23. Define susceptibility. Is the value of susceptibility for a diamagnetic substance positive
or negative?
Q.24. Write the order of frequency range of each of the following electromagnetic radiations
(i) Microwaves (ii) Ultraviolet rays (iii) Gamma-
Gamma rays.

SECTION - D
Q.25. Derive an expression for the electrostatic potential energy of a system of point charges.
Q.26. State Gauss theorem and apply it to find the electric field at a point due to a plane sheet
of charge.
Q.27. Derive an expression for the torque acting on an electric dipole, which is held in a
uniform electric field, when the axis of the dipole makes an angle θ with the electric

Q.28. Deduce Ohm's law from elementar
elementary
y ideas and hence write an expression for resistance
and resistivity.
Q.29. State Biot-Savart
Savart law and apply it to find the magnetic field due to a circular loop
carrying current at a point on the axis.
OR
What is radial magnetic field? What is its importance in a moving coil galvanometer?
How is a radial magnetic field achieved in moving coil galvanometers?
Q.30. Deduce an expression for the mutual inductance of two long co
co-axial
axial solenoids but
having different radii and different number of turns.
Q.31. Find the expression for the magnetic moment when an electron revolves at a speed ‘v’,
around an orbit of radius ‘r’ in hydrogen atom hence define Bohr’s magneton.
SECTION - E
Q.32. Two straight long parallel conductors carry currents I1 and I2 in the opposite direction.
Deduce the expression for the force per unit length between them. Hence define 1
ampere current.
OR
A point charge q moving with speed v enters a uniform magnetic
field B that is acting into the plane of the paper as shown.
(a) Write the equation of force on a charge particle in a
magnetic field.
(b) What is the path followed by the charge q and in which plane
does it move?
(c) How does the path followed by the charge get affected if its velocity has a
component parallel to B?
(d) If an electric field E is also applied such that the particle continues moving along
the original straight-line
line path, find the magnitude and direction of the electric field
E?
Q.33. What is a Wheatstone bridge? Deduce the condition for which Wheatstone bridge is
balanced? Write one application of Wheatstone bridge.
OR
State Kirchhoff’s current law and voltage law.
A cell E1 of EMF 6 volt and internal resistance 2 ohm is
connected with another cell E2 of EMF 4 volt and
internal resistance 8 ohm as shown in the figure. Find
the potential difference across points X and Y.
Q.34. Derive an expression for the capacitance of a parallel
parallel plate capacitor with (a) a
dielectric slab (b) a metallic plate in between the plates of the capacitor.

OR
Define electric potential at a point. Derive an expression for the electric potential at a
point due to a point charge. Does the potential increase
increase or decrease in the direction of
electric field.

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