ICSE Class 10 Physics Previous Year Question Paper 2019

Question 1
(a) The diagram below shows a claw hammer used to remove a nail;

   (i) To which class of lever does it belong?
   (ii) Given one more example of the same class of lever mentioned by you in (i) for which the mechanical advantage is greater             than one.

(b) Two bodies A and B have masses in the ratio 5:1 and their kinetic energies are in the ratio 125:9. Find the ratio of their                 velocities.

(c)
   (i) Name the physical quantity which is measured in calories.
  (ii) How is calories related to the S.I. unit of that quantity?

(d)
   (i) Define couple.
  (ii) State the S.I. unit of moment of couple.

(e)
   (i) Define critical angle.
   (ii) State one important factor which affects the critical angle of a given medium.

Question 2
(a) An electromagnetic radiation is used for photography in fog.
   (i) Identify the radiation.
   (ii) Why is this radiation mentioned by you, ideal for this purpose?

(b)
  (i) What is the relation between the refractive index of water with respect to air (_a𝜇_w) and the refractive index of air with respect to water (_w𝜇_a).
  (ii) If the refractive index of water with respect to air (_a𝜇_w) is 
Calculate the refractive index of air with respect to water (_w𝜇_a).

(c) The specific heat capacity of a substance A is 3,800 Jkg^-1K ^-1 and that of a
     substance B is 400 Jkg^-1K^-1 Which of the two substances is a good conductor of heat? Give a reason for your answer.

(d) A man playing a flute is able to produce notes of different frequencies. If he closes the holders near his mouth, will the pitch of       the note produced, increase or decrease? Given a reason.

(e) The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. Complete the path       of the ray PQ till it emerges out of the block. [Write necessary angles.]

Question 3
(a) 
  (i) If the lens is placed in water instead of air, how does its focal length change?
  (ii) Which lens, thick or thin has greater focal length?

(b) Two waves of the same pitch have amplitudes in the ratio 1: 3.
What will be the ratio of their:
  (i) Intensities and
  (ii) Frequencies?

(c) How does an increase in the temperature affect the specific resistance of a: 
  (i) Metal and
  (ii) Semiconductor?

(d)
  (i) Define resonant vibrations.
  (ii) Which characteristic of sound, makes it possible to recognize a person by his voice without seeing him?

(e) It is possible for a hydrogen (H) nucleus to emit an alpha particle?

Question 4
(a) Calculate the effective resistance across AB:

(b) 
   (i) State whether the specific heat capacity of a substance remains the same when its state changes from solid to liquid.
   (ii) Given one example to support your answer.

(c) A magnet kept at the centre of two coils A and B is moved to  and fro as shown in the diagram. The two galvanometers show deflection.

    State with a reason whether:
    x > y
   or
   x < y. [x and y are magnitudes of deflection.]

(d)
  (i) Why a nuclear fusion reaction is called a thermos nuclear reaction?
  (ii) Complete the reaction:
 ³He₂ + ²H₁ → ⁴He₂  +................+ Energy 

(e) State two ways to increase the speed of rotation of a D.C. motor.

Question 5
(a) A body of mass 10 Kg is kept at a height of 5 m. It is allowed to fall and reach the ground.
   (i) What is the total mechanical energy possessed by the body at the height of 2 m assuming it is a frictionless medium?
  (ii) What is the kinetic energy possessed by the body just before hitting the ground? Take g = 10m /s².

(b) A uniform meter scale is in equilibrium as shown in the diagram:

  (i) Calculate the weight of the meter scale.
  (ii) Which of the following options is correct to keep the ruler in equilibrium when 40 gf wt is shifted to 0 cm mark?
   F is shifted towards 0 cm.
        or
   F is shifted towards 100 cm.

(c) The diagram below shown a pulley arrangement:

(i) Copy the diagram and mark the direction of tension on each stand of the string.
(ii) What is the velocity ratio of the arrangement?
(iii) If the tension acting on the string is T, then what is the relationship between T and effort E?
(iv) If the free end of the string moves through a distance x, find the distance by which the load is raised.

Question 6
(a) How does the angle of deviation formed by a prism change with the increase in the angle of incidence? 
     Draw a graph showing the variation in the angle of deviation with the angle of incidence at a prism surface.

(b) A virtual, diminished image is formed when an object is placed between the optical centre and the principal focus of a lens.
  (i) Name the type of lens which forms the above image.
  (ii) Draw a ray diagram to show the formation of the image with the above stated characteristics.

(c) An object is placed at a distance of 24 cm from a convex lens of focal length 8 cm.
  (i) What is the nature of the image so formed?
  (ii) Calculate the distance of the image from the lens.
  (iii) Calculate the magnification of the image.

Question 7
(a) It is observed that during march-past we hear a base drum distinctly from a distance compared to the side drums. [3]
  (i) Name the characteristic of sound associated with the above observation.
  (ii) Given a reason for the above observation.

(b) A pendulum has a frequency of 4 vibrations per second. An observer starts the pendulum and fires a gun simultaneously. He           hears the echo from the cliff after 6 vibrations of the pendulum. If the velocity of sound in air is 340 m/s, find the distance             between the cliff and observer.

(c) Two pendulums C and D are suspended from a wire as shown in the figure given below. Pendulum C is made to oscillate by             displacing it from its mean position. It is seen that D also starts oscillating.

 (i) Name the type of oscillation, C will execute.
 (ii) Name the type of oscillation, D will execute.
 (iii) If the length of D is made equal to C then what difference will you notice in the oscillations of D?
 (iv) What is the name of the phenomenon when the length of D is made equal to C?

Question 8
(a)
  (i) Write one advantage of connecting electrical appliance in parallel combination.
 (ii) What characteristic should a fuse wire have?
 (iii) Which wire in a power circuit is connected to the metallic body of the appliance?

(b) The diagram below shows a dual control switch circuit connected to a bulb.

(i) Copy the diagram and complete it so that bulb is switch ON.
(ii) Out of A & B which one is the live wire and which one is the neutral wire?

(c)

The diagram above shows a circuit with the key k open. Calculate:
  (i) the resistance of the circuit when the key k is open.
  (ii) the current drawn from the cell when the key k is open.
  (iii) the resistance of the circuit when the key k is closed.
  (iv) the current drawn from the cell when the key k is closed.

Question 9
(a)
  (i) Define Calorimetry.
  (ii) Name the material used for making a Calorimeter.
  (iii) Why is a Calorimeter made up of thin sheets of the above material answered in (ii)?

(b) The melting point of naphthalene is 80°C and the room temperature is 30°C. A sample of liquid naphthalene at 100°C is cooled       down to the room temperature.
     Draw a temperature time graph to represent this cooling. In the graph, mark the region which corresponds to the freezing               process.

(c) 104 g of water at 30°C is taken in a calorimeter made of copper of mass 42g. When a certain mass of ice at 0°C is added to it, 
    temperature of the mixture after the ice has melted, was found to be 10°
   C. Find the mass of ice added.
   [Specific heat capacity of water = 4.2 Jg ^-1°C^-1 ; Specific latent heat of fusion of ice = 336Jg^-1 ; Specific heat capacity of
    copper = 0.4 J g ^-1 °C^-1]

Question 10
(a) Draw a neat labeled diagram of an A.C. generator.

(b)
  (i) Define nuclear fission.
  (ii) Rewrite and complete the following nuclear reaction by filling in the atomic number of Ba and mass number of Kr:
        

(c) The diagram below shows a magnetic needle kept just below the conductor AB which is kept in North South direction.

  (i) In which direction will the needle deflect when the key is closed?
  (ii) Why is the deflection produced?
  (iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB?
  (iv) Name one device which work on this principle.

Answer 1
(a)
  (i) The hammer is an example of a class 1 lever.
   (ii) The crow bar is a class 1 lever which has a long handle, i.e. its effort arm > load arm; thus, its MA > 1.

(b)
 (i) Kinetic energy is given as
     

      K.E_A: K.E_B = 125:9
      m_a:m_{b= 5:1}
     Taking ratio of Kinetic enrgy of A to kinetic energy of body B,

Thus, the ratio of the velocities of body A and B, vA:vB = 5:3.
(ii) Heat is measured in calories.

(c)
  (i) Heat energy is measured in calories.
  (ii) SI unit of energy is Joule (J).
      Relation between calories and joules is
      1 calorie (1 cal) = 4.186 J

(d)
  (i) Two equal and opposite parallel forces not acting along a same line which produce rotation is called a couple.
  (ii) The SI unit of the moment of couple is Newton-metre (Nm).

(e)
  (i) The angle of incidence in the denser medium corresponding to the angle of refraction in the rarer medium is 90ᵒ and is called           the critical angle.
  (ii) Factors affecting the critical angle: (any one)
     1)Wavelength of light
     2)Temperature

Answer 2
(a)
  (i) Infrared radiation is suitable electromagnetic radiation for photography in fog.
  (ii) It is because these radiations are not much scattered and can penetrate through the fog.

(b)
  (i) Refractive index of water with respect to air is denoted by _aμ_w  .
   And refractive index of air with respect to water is denoted by _wμ_a .
   By the principle of reversibility,
   

 (ii) It is given that

   
  Thus, by the principle of reversibility,
   
  Thus, the refractive index of air with respect to water is 0.6.
(c) Specific heat of substance A = 3800 Jkg^-1 K ^-1
    Specific heat of substance B = 400 Jkg^-1 K ^-1
     A good conductor of heat has low specific heat and a bad conductor of heat has high specific heat. Thus, substance B is a good       conductor of heat.

(d)In case of a flute where the holes near the mouth are closed, a pitch of a lower note is produced. Thus, the pitch of the note           produced decreases.

(e) 

Answer 3
(a)
  (i) If a lens is placed in water instead of air, its focal length increases.
  (ii) A thin lens has a greater focal length than a thick lens.

(b)
  (i) Ratio of amplitudes of waves with the same pitch is 1:3.
   Intensity of sound is directly proportional to the square of the amplitude.
  Thus,

(ii) Frequency of sound is independent of amplitude.
   Thus, f₁:f₂ = 1:1

(c)
  (i) For metals, with increase in temperature, the specific resistance increases.
  (ii) For semiconductors, the specific resistance decreases with increase in temperature.

(d)
  (i) When the frequency of the externally applied periodic force on the body is equal to its natural frequency, the body begins to           vibrate with large amplitude. Such vibrations are called resonant vibrations.
  (ii) The characteristic of sound called quality enables us to recognise the person by his voice and without seeing him.

(e) No, the hydrogen nucleus H₁¹ cannot emit alpha particles as they have insufficient amount of neutrons and protons in the               nucleus.

Answer 4
(a)Combination of resistors in the question can be drawn in the simplified way as shown below:
    Now,

  Resistors of 5 Ω and 4 Ω are in series.
  Thus, Rs = 5 Ω + 4 Ω = 9 Ω
   This series combination is in parallel to the 3 Ω resistor.
   Thus,
   
  This whole combination is in series with the 8 Ω resistor.
  Thus,
  Effective resistance between A and B is 10.25 Ω.

(b)
 (i) The specific heat capacity of a substance changes when its state changes from solid to liquid.
 (ii) The specific heat capacity of water is 4200 JK^-1kg^-1.
    In the solid state (ice): 2100 JK^-1kg^-1
     In the vapour state (steam): 460 JK^-1kg^-1

(c) x < y
  This is because the number of turns of coil is maximum in coil B rather than in coil A.
  Thus, deflection of x will be less than deflection of y.

(d)
  (i) Nuclear fusion is not possible at normal temperature. At high temperature and due to thermal agitations, both nuclei acquire
    sufficient kinetic energy to overcome the force of repulsion between them when they approach each other and thus get fused.
    Thus, the nuclear fusion reaction is also called a thermonuclear reaction.
(ii) ³He₂ + ²H₁ → ⁴He₂ + ¹H₁ + Energy

(e) Ways to increase the speed of rotation of a DC motor: (any two)
   1. By increasing the strength of current in the coil
   2. By increasing the number of turns in the coil
   3. By increasing the area of the coil
   4. By increasing the strength of the magnetic field

Answer 5
(a) i. As the medium is frictionless, the total mechanical energy will be conserved.
  ME = PE + KE
  at highest point KE = 0,PE = mgh = 10 ×10× 5=500J
  ME = 500 + 0 = 500J
  At height of 2m the total mechanical energy will be 500J
ii.
  Just before hitting the ground
  PE will become zero
  And we know that ME will remain
  conserved as the medium is frictionless
 ME=KE+PE
  500=KE+0
  Hence
  KE=500J

(b)i.
  Let the weight of the meter scale be m kgF
  Meter scale has uniform distribution of mass through out
   weight will act at its middle point
  Then according to the principle of moments
  Clockwise moment=anti clockwise moment
  m× 50-30 =40× (30-5)
  m×20=40×25
  m=50kgF

 ii. F is shifted towards 0 cm.

(c) i.

 ii. Velocity ratio = 2
 iii. The relation between T and E is given by T = E
 iv. If the free end of the string moves through a distance x, then the load will be raised by a distance 

Answer 6
(a)As the angle of incidence increases, the angle of deviation first decreases, reaches to a maximum value for a critical angle of          incidence, and then on further increasing the angle of incidence, the angle of deviation begins to increase.

(b)
   i.concave lens
   ii.

(c) i. Real and inverted
    ii. u = -24 cm
   f = 8 cm
   According to lens formula

Answer 7
(a) i. Loudness
   ii. The amplitude of vibration of medium particles is very large in the base drum compared to the side drum. The frequency of             vibration of medium particles is also very low compared to the side drum.

(b) Let the distance between cliff and the observer be d
    distance travelled by sound=2d
   the pendulum has a frequency of 4 vibration per second
   time taken by the pendulum to complete 6 vibrations is
   

(c)
  i. Natural or free oscillation
  ii. Forced oscillation
  iii.The natural frequency of D becomes equal to C, and therefore, there is exchange of energy between C and D. Pendulum D               starts oscillating slowly with small amplitude, and it ultimately acquires the same amplitude which pendulum C initially had.
  iv. Resonance