Plus Two Physics Model Question Paper 5

Kerala Plus Two Physics Model Question Paper 5

Time: 2 Hours
Cool off time : 15 Minutes

General Instructions to candidates:

  • There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hrs.
  • Your are not allowed to write your answers nor to discuss anything with others during the ‘cool off time’.
  • Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
  • Read questions carefully before you answering.
  • All questions are compulsory and only internal choice is allowed.
  • When you select a question, all the sub-questions must be answered from the same question itself.
  • Calculations, figures and graphs should be shown in the answer sheet itself.
  • Malayalam version of the questions is also provided.
  • Give equations wherever necessary.
  • Electronic devices except non programmable calculators are not allowed in the Examination Hall.

Plus Two Physics Previous Year Question Papers and Answers 2018

Speed of light, c = 3 x 108m/s
Mass of proton, mp = 1.6726 x 10-27 kg
Mass of neutron, mn = 1.6749 x 10-27 kg
Planck’s constant, h = 6.626 x 10-34 Js
1eV=1.6 x 10-19 J

Questions 1-7 carry 1 score each. Answer any six questions.
Plus Two Physics Model Question Papers Paper 5 1.

Question 1.
Write the expression for intensity of electric field near to the surface of a charged conductor with uniform charge density σ.
Plus Two Physics Model Question Papers Paper 5 1

Question 2.
The unit of electrical resistivity is…………
Plus Two Physics Model Question Papers Paper 5 2

Question 3.
E.m.f can be induced in a coil placed in an external magnetic field by:
a. Changing the intensity of magnetic field
b. Changing the area of coil
c. Changing the orientation of the coil
d. All of the above
Plus Two Physics Model Question Papers Paper 5 3

Question 4.
Write the energy and momentum associated with a moving photon.
Plus Two Physics Model Question Papers Paper 5 4

Question 5.
The value of relative permeability of a dia magnetic material is;
Plus Two Physics Model Question Papers Paper 5 5

Question 6.
The electric field amplitude of an electromagnetic wave is 15V/m. Find the magnetic field amplitude of the wave.
Plus Two Physics Model Question Papers Paper 5 6

Question 7.
A convex lens is placed in a medium having refractive index greater than that of the lens. The lens now behaves as;
a. Converging lens
b. Diverging lens
c. Plane glass plate
d. None of the above
Plus Two Physics Model Question Papers Paper 5 7

Questions 8 to 15 carry 2 score each. Answer any 7 questions
Plus Two Physics Model Question Papers Paper 5 8.

Question 8.
a. ‘Electrostatic field is always normal to the surface of a charged conductor’. Justify the statement.
b. The value of electric potential at the surface of a charged conductor is 10 V. Find the value of intensity of electric field and potential at a point interior to it
Plus Two Physics Model Question Papers Paper 5 8
Plus Two Physics Model Question Papers Paper 5 8.1

Question 9.
A galvanometer with a coil of resistance 12 Ω shows a lull scale deflection for a current of 2.5 mA. How can it be converted into an ammeter of range 7.5 A?
Plus Two Physics Model Question Papers Paper 5 9

Question 10.
The curves shown in figure are drawn for different magnetic materials. Among the three curves, name the curve that
Plus Two Physics Model Question Papers Paper 5 10
a. Represent the material usually used for making permanent magnets.
b. Represent the material usually used for making electromagnets.
Plus Two Physics Model Question Papers Paper 5 10.1

Question 11.
A capacitor C, a variable resistance R and a bulb B are connected in series to a.c mains in the circuit as shown. The bulb glows with some brightness. How the glow of the bulb change if.
Plus Two Physics Model Question Papers Paper 5 11
a. A dielectric slab is introduced between the plates of the capacitor
b. The resistance R is increased keeping the same capacitance
Plus Two Physics Model Question Papers Paper 5 11.1

Question 12.
James Clerk Maxwell modified Ampere’s circuital theorem by introducing the concept of displacement current.
a. What do you mean by displacement current?
b. Write down the equation for displacement current.
Plus Two Physics Model Question Papers Paper 5 12

Question 13.
An object AB is kept in front of a concave mirror as shown in figure.
Plus Two Physics Model Question Papers Paper 5 13
Plus Two Physics Model Question Papers Paper 5 13.1
a. Complete the ray diagram showing the image formation of object
b. How will the position and intensity of image be affected if the lower half of the mirror’s reflecting surface is painted black?
Plus Two Physics Model Question Papers Paper 5 13.2

Question 14.
Assuming that the two diodes D1 and D2 used in the electric circuit as shown in figure are ideal. Find out the value of current flowing through 2.5 Ω resistor.
Plus Two Physics Model Question Papers Paper 5 14

Question 15.
a. Mention the function of the following used in the communication system
i. Transducer
ii. Transmitter
b. Figure shows the block diagram of a AM transmitter. Identify the boxes X and Y.
Plus Two Physics Model Question Papers Paper 5 15
Plus Two Physics Model Question Papers Paper 5 15.1

Questions 16 to 22 carry 3 scores each. Answer any 6 questions.
Plus Two Physics Model Question Papers Paper 5 16.

Question 16.
Three capacitors of capacitances 2µF, 3µF and 4µF are connected in series.
a. Find the equivalent capacitance of the combination.
b. The plates of a parallel plate capacitor have an area 20 cm² each are separated by a distance of 2.5 mm. The capacitor is charged by connecting it to a 400V supply. How much electrostatic energy is stored in the capacitor?
Plus Two Physics Model Question Papers Paper 5 16

Question 17.
A circuit using potentiometer and a battery of. negligible internal resistance is set up as shown to develop a constant potential gradient along the wire PQ. Two cells of e.m.f s E1 and E2 are connected in series as in figure in combination 1 and 2. The balance points are obtained respectively at 400 cm and 240 cm from point P. Find
Plus Two Physics Model Question Papers Paper 5 17
Plus Two Physics Model Question Papers Paper 5 17.1

Question 18.
A conducting rod PQ of length ‘ l ’ connected to a resistance ‘R’ is moved at a uniform speed ‘ V’, normal to a uniform magnetic field ‘B’
Plus Two Physics Model Question Papers Paper 5 18
a. Deduce the expression for e.m.f induced in the conductor
b. Find the magnitude and direction of current through the conductor
Plus Two Physics Model Question Papers Paper 5 18.1

Question 19.
In tuner circuits, we use the phenomenon of resonance.
a. Write the condition of resonance in series LCR circuit
b. A series LCR circuit uses L = 0. 1 H,C = 10µF and R = 100Ω. Find the value of frequency at which the amplitude of current is maximum
Plus Two Physics Model Question Papers Paper 5 19

Question 20.
The focal length of a lens has dependence on its radii of curvatures and refractive index. Derive Lens maker’s formula
Plus Two Physics Model Question Papers Paper 5 20

Question 21.
a. Write the expression for the de Broglie wavelength associated with a charged particle having charge ‘q’ and mass ‘m’, when it is accelerated by a potential of ‘V’ volts.
b. A proton and an electron have same kinetic energy. Which one has greater value of de Broglie wavelength and why?
Plus Two Physics Model Question Papers Paper 5 21

Question 22.
Find the binding energy per nucleon of 2040Ca nucleus. Given m 2040Ca = 39.962589u.
mp = 1.00783u, mn = 1.00867u
Take 1 amu = 931 MeV/c2
Plus Two Physics Model Question Papers Paper 5 22

Questions from 23-26 carry 4 score. Answer any 3 questions.
Plus Two Physics Model Question Papers Paper 5 22.

Question 23.
Gauss’s theorem is useful for finding the intensity of electric field.
a. Write the Gauss’s law in its mathematical form
b. Using the law, prove that intensity of electric field at a point due to a uniformly charged infinite plane sheet is independent of the distance from it
Plus Two Physics Model Question Papers Paper 5 23

Question 24.
a. Express Ohm’s law in terms of current density, electrical resistivity and intensity of electric field
b. Explain the variation of resistance of a semiconductor with temperature. Also draw the graph showing the variation of resistivity of silicon with temperature
Plus Two Physics Model Question Papers Paper 5 24

Question 25.
The relation between magnetic field and current is given by Biot-Savart’s law.
a. Write the expression for the magnetic field at point along the axis of a circular loop of radius ‘R’ carrying a current ‘I’.
b. From the above expression. Find the value of magnetic field at the centre of the loop
c. Sketch the magnetic field lines for current carrying circular loop
Plus Two Physics Model Question Papers Paper 5 25

Question 26.
Plus Two Physics Model Question Papers Paper 5 26
a. Identify the diode in the circuit and write the use of the resistance Rs
b. Explain how the diode helps as to stabilize the output voltage of the circuit
c. Name the type of biasing used in this diode
Plus Two Physics Model Question Papers Paper 5 26.1
Plus Two Physics Model Question Papers Paper 5 26.2

Questions 27 to 29 carry 5 scores. Answer any 27 – 29 carry 5 score. Answer any 2 questions
Plus Two Physics Model Question Papers Paper 5 27

Question 27.
In the figure, PQ is the incident ray on the equilateral glass prism ABC.
Plus Two Physics Model Question Papers Paper 5 27.1
a. Complete the ray diagram showing the passage of light and mark angle of deviation.
b. Derive an expression for the refractive index of the material of the prism
Plus Two Physics Model Question Papers Paper 5 27.2

Question 28.
According to Christian Huygens wave theory, light emanating from a source as wave fronts.
a. What is the shape of wave front emerging form a linear source?
b. Derive the mathematical expression for the bandwidth of interference bands obtained in young’s double slit experiment with the help of suitable diagram
Plus Two Physics Model Question Papers Paper 5 28

Question 29.
a. The radius of nth stationary orbit of hydrogen atoms is :
Plus Two Physics Model Question Papers Paper 5 29
Using Bohr postulates, obtain an expression for the energy of electron in the stationary states of H-atom
Plus Two Physics Model Question Papers Paper 5 29.
b. Draw the energy level diagram showing how the spectral lines corresponding to Balmer series occur due to transition between the energy levels
Plus Two Physics Model Question Papers Paper 5 29.1

Answers

Answer 1.
\(E=\frac { \sigma }{ { \varepsilon }_{ 0 } } \)

Answer 2.
Ωm

Answer 3.
(d)All the above

Answer 4.
E = hυ = bc/λ
\(P=\frac { h }{ \lambda } =\frac { h\upsilon }{ c } \)

Answer 5.
µr < 1 or µr = 0

Answer 6.
Plus Two Physics Model Question Papers Paper 5 6

Answer 7.
b. Diverging lens

Answer 8.
a. If E is not normal, there is a component a long the tangent to the surface. Then free charge on the surface experience force and will move. But E should have no tangential component in static situation.
OR
V is constant on the surface, therefore E should be normal.
b. E = 0, V = 10V

Answer 9.
G = 12V, Ig = 2.5×10-3 A
I = 7.5 A
Plus Two Physics Model Question Papers Paper 5 9
Putting the low resistance S in parallel with the galvanometer

Answer 10.
a. A
b. C

Answer 11.
Plus Two Physics Model Question Papers Paper 5 11
a. Er introduced, capacitance increases i.e,.\(\frac { 1 }{ c\omega } \) will decrease ∴ I0 will be increase so the brightness will be increased
b. R ↑, I↓ brightness ↓
resistance cause decrease in I0 ∴ bright ness will be decreased

Answer 12.
a. Displacement current is current due to time varying electric flax
Plus Two Physics Model Question Papers Paper 5 12

Answer 13.
Plus Two Physics Model Question Papers Paper 5 13
b.No change in position intensity halved/reduced

Answer 14.
D2 on reverse biasing so it does not conduct
D1 on forward biasing so it conduct
R = 3 + 2.5 = 5.5
V = 10V
I = \(\frac { V }{ R }\) = \(\frac { 10 }{ 5.5 }\) = l.82A

Answer 15.
a. i. Convert energy from one form to an other.
ii. Convert message signal to modulated signal for transmission.
b. X → modulater
Y → Power amplifier

Answer 16.
Plus Two Physics Model Question Papers Paper 5 16

Answer 17.
E α l
Plus Two Physics Model Question Papers Paper 5 17
Plus Two Physics Model Question Papers Paper 5 17.1

Answer 18.
a. The magnetic flux linked with the rectangular loop PQRS is φ = BA = Blx
According to Faraday’s law, induced emf is
Plus Two Physics Model Question Papers Paper 5 18

Answer 19.
a. V= VC
XL = XC
Plus Two Physics Model Question Papers Paper 5 19

Answer 20.
Plus Two Physics Model Question Papers Paper 5 20
Plus Two Physics Model Question Papers Paper 5 20.1

Answer 21.
Plus Two Physics Model Question Papers Paper 5 21

Answer 22.
BE = Eb = ∆mc²
= (Zmp + (A-Z) Mn – M) c²
= (20 x 1.00783 + 20 x 1.00867 – 39.962589) x
Plus Two Physics Model Question Papers Paper 5 22

Answer 23.
Plus Two Physics Model Question Papers Paper 5 23

Answer 24.
a. I = ne A Vd……….(1)
Plus Two Physics Model Question Papers Paper 5 24

Answer 25.
Plus Two Physics Model Question Papers Paper 5 25

Answer 26.
a. Zener diode
Any change in input voltage results in change in voltage drop across Rs. without any change in voltage across zener diode.
b. When Vi increases, main current increases, Iz increases with no change in load current IL. So that V0 = Vz = IL RL. When Vi decreases, Iz decreases with no change in IL.
c. Reverse biasing

Answer 27.
Plus Two Physics Model Question Papers Paper 5 27

Answer 28.
a. Cylinder
b. S1 and S2 are two narrow slits separated by a distance “d”. They are illuminated by a monochromatic source of wavelength λ . A screen is placed at a distance of D from the slits as shown in the figure
Plus Two Physics Model Question Papers Paper 1 29
Light waves from S1 and S2 reach the point P. The path difference between these two waves is S2N.
Plus Two Physics Model Question Papers Paper 1 29.1
Plus Two Physics Model Question Papers Paper 1 29.2

Answer 29.
a. For a hydrogen atom, gives the expression to determine the energies of different energy states. But then this equation requires the radius r of the electron orbit. To calculate r, Bohr’s second postulate about the angular momentum of the electron-the quantization condition is used. The angular momentum L is given by
L = mvr
Bohr’s second postulate of quantization says that the allowed values of angular momentum are integral multiples of h/2π
Plus Two Physics Model Question Papers Paper 5 29
where n is an integer, rn is the radius of nth possible orbit and un is the speed of moving electron in the nth orbit. The
allowed orbits are numbered 1,2,3………
according to the values of n, which is called the principal quantum number of the orbit.
From the relation between un and rn is
Plus Two Physics Model Question Papers Paper 5 29.1
Plus Two Physics Model Question Papers Paper 5 29.2

Plus Two Physics Previous Year Question Papers and Answers

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