ICSE Class 10 Physics Previous Year Question Paper 2016

Question 1
(a)
 (i) Give an example of a non contact force which is always of attractive nature.
 (ii) How does the magnitude of this non contact force on the two bodies depend on the distance of separation between them?

(b)A boy weighing 40 kgf climbs up a stair of 30 steps each 20 cm high in 4 minutes and a girl weighing 30 kgf does the same in 3     minutes. Compare:
  (i) The work done by them.
  (ii) The power developed by them.

(c) With reference to the terms Mechanical Advantage, Velocity Ratio and efficiency of a machine, name and define the term that         will not change for machine of a given design.

(d)Calculate the mass of ice required to lower the temperature of 300 g of water 40ºC to water at 0ºC.
    (Specific latent heat of ice = 336 J/g, Specific heat capacity of water = 4.2J/gºC)

(e) What do you understand by the following statements:
  (i) The heat capacity of the body is 60JK^-1
  (ii) The specific heat capacity of lead is 130 Jkg^-1K^-1.

Question 2
(a)State two factors upon which the heat absorbed by a body depends.

(b)A boy uses blue colour of light to find the refractive index of glass. He thenrepeats the experiment using red colour of light. Will      the refractive index be the same or different in the two cases? Give a reason to support your answer.

(c) Copy the diagram given below and complete the path of the light ray till it emerges out of the prism. The critical angle of glass         is 42º In your diagram mark the angles wherever necessary.

(d)State the dependence of angle of deviation:
   (i) On the refractive index of the material of the prism.
   (ii) On the wavelength of light

(e)The ratio of amplitude of two waves is 3:4. What is the ratio of their:
   (i) loudness?
   (ii) Frequencies?

Question 3
(a)State the ways by which the frequency of transverse vibrations of a stretchstring can be increased.

(b)What is meant by noise pollution? Name one source of sound causing noise pollution.

(c) The V-I graph for a series combination and for a parallel combination of two resistors is shown in the figure below. Which of the      two A or B. represents the parallel combination? Give reasons for your answer.

(d)The music system draws a current of 400 mA when connected to a 12 V battery.
   (i) What is the resistance of the music system?
   (ii) The music system if left playing for several hours and finally the battery voltage drops to 320 mA and the music system stops          playing when the current.

(e) Calculate the quantity of heat produced in a 20Ω resistor carrying 2.5 A current in 5 minutes.

Question 4
(a)State the characteristics required of good thermion emitter.

(b)An element _ZS^A decays to ₈₅R²²² after emitting 2 α particles and 1 β particle.
     Find the atomic number and atomic mass of the element S.

(c) A radioactive substance is oxidized. Will there be any change in the nature its radioactivity? Give a reason for your answer.

(d) State the characteristics required in a material to be used as an effective fuse wire.

(e) Which coil of a step up transformer is made thicker and why?

Question 5
(a)A stone of mass ‘m’ is rotated in a circular path with a uniform speed by tying a strong string with the help of your hand.
    Answer the following questions:
  (i) Is the stone moving with a uniform or variable speed?
  (ii) Is the stone moving with a uniform acceleration? In which direction does the acceleration act?

(b)From the diagram given below. answer the question that follow:

  (i) What kind of pulleys are A and B?
  (ii) State the purpose of pulley B.
  (iii) What effort has to be applied at C just raise the load L = 20 kgf?
  (Neglect the weight of pulley A and friction)

(c)
  (i) An effort is applied on the bigger wheel of a gear having 32 teeth. It is used to turn a wheel of 8 teeth. Where it is used.
  (ii) A pulley system has three pulleys. A load of 120 N is overcome by applying an effort of 50N. Calculate the Mechanical                     Advantage and Efficiency of this system.

Question 6
(a)
  (i) What is the principle of method of mixtures?
  (ii) What is the other name given to it?
  (iii) Name the law on which the principle is based

(b)Some ice is heated at a constant rate, and its temperature is recorded after every few seconds, till steam is formed at 100ºC.           Draw a temperature time graph to represent the change. Label the two phase changes in your graph.

(c) A copper vessel of mass 100 g contains 150 g of water at 50ºC. How much ice is needed to cool it to 5ºC? [4] Given: Specific        heat capacity of copper = 0.4 Jg-1 ºC ^-1
    Specific heat capacity of water = 4.2 Jg-1 ºC^-1
    Specific latent heat of fusion ice = 336 Jg^-1

Question 7
(a) 
  (i) Write a relationship between angle of incidence and angle of refractions for a given pair of media.
  (ii) When a ray of light enters from one medium to another having different optical densities it bends. Why does this phenomenon         occur?
 (iii) Write one conditions where it does not bend when entering a medium of different optical density.

(b)A lens produces a virtual image between the object and the lens.
   (i) Name the lens.
   (ii) Draw a ray diagram to show the formation of this image.

(c) What do you understand by the term’ Scattering of light’? Which colour of white light is scattered the least and why?\

Question 8
(a) 
  (i) Name the waves used for echo depth sounding.
  (ii) Give one reason for their use for the above purpose.
  (iii) Why are the waves mentioned by you not audible to us?

(b) 
  (i) What is an echo
  (ii) State two conditions for an echo to take place.

(c) 
  (i) Name the phenomenon involved in tunning a radio set to a particular station.
  (ii) Define the phenomenon named by you in part (i) above.
  (iii) What do you understand by loudness of sound?
  (iv) In which units is the loudness of sound measured?

Question 9
(a)
  (i) Which particles are responsible for current in conductors?
  (ii) To which wire of a cable in a power circuit should the metal case of a geyser be connected?
  (iii) To which wire should the fuse be connected?

(b) 
  (i) Name the transformer used in the power transmitting station of a power plant.
  (ii) What type of current is transmitted from the power station?
  (iii) At what voltage is this current available to our household?

(c) A battery of emf 12 V and internal resistance 2 Ω is connected with two resistors A and B of resistance 4 Ω and 6 Ω respectively joined in series.

Find:
  (i) Current in the circuit
  (ii) The terminal voltage of the cell.
  (iii) The potential difference across 6Ω Resistor.
  (iv) Electrical energy spent per minute in 4Ω resistor.

Question 10
(a)Arrange α, β, and γ rays in ascending order with respect to their
  (i) Penetrating power.
  (ii) Lionising power.
  (iii) Biological effect.

(b) 
  (i) In a cathode ray tube what is the function of anode?
  (ii) State the energy conversion taking place in a cathode ray tube.
  (iii) Write one use of cathode ray tube.

(c) 
  (i) Represent the change in the nucleus of a radioactive element when a β particle is emitted.
  (ii) What is the name given to elements with same mass number and different atomic number
  (iii) Under which conditions does the nucleus of an atom tend to radioactive?

Answer 1
(a)
  (i) The gravitational force is always attractive in nature.
  (ii) The magnitude of non-contact forces acting on two bodies depends on th distance of separation between them. The                      magnitude  of force decreases with an increase in separation and increases as the separation decreases. It varies inversely as          the square of the distance of separation.

(b)Given:
  Force of gravity of the boy, F_b = 40 kgf
  Time taken by him, t_b = 4 minutes = 4 × 60 s = 240 s
  Force of gravity of the girl, Fg = 30 kgf
  Time taken by her, t_g = 3 minutes = 3 × 60 s = 180 s
  Distance covered by both in 30 steps is
  D = 30 × 20 = 600 cm
  While climbing, both have to do work against the force of gravity.
 (i) Work done by the boy in climbing the stairs:
   W_b = F × D = 40 kgf × 600 cm
   W_b = 24000 J
   Work done by the girl in climbing the stairs:
   W_g = F × D = 30 kgf × 600 cm
    W_g = 18000 J

(ii)

   
   Thus, power developed by them is 1 : 1

(c) Velocity ratio.
    It is the ratio of the velocity of effort to the velocity of load.

(d)Let m be the mass of the ice to be added.
   Heat energy required to melt to lower the temperature is = mL = m × 336
   Heat energy imparted by the water in fall of its temperature from 40°C to
   0°C = mass of the water × specific heat capacity × fall in temperature
  = 300 × 4.2 × 40°C
   If there is no loss of heat,
   m × 336 J/g = 300 g × 4.2 J/g°C × 40°C

(e)
   (i) Heat capacity is the amount of heat required to raise the temperature of a body by 1ºC or 1 K. Thus, 60 JK⁻¹
     of energy is required to raise the temperature of the given body by 1 K.
  (ii) Specific heat capacity is the amount of heat energy required to raise the temperature of unit mass of a substance through 1ºC        or 1 K.
      Thus, 130 Jkg⁻¹K ⁻¹ of heat energy required to raise the temperature of unit mass of lead through 1 K.

Answer 2
(a)Heat absorbed by a body depends on the mass of the body and the specific heat capacity of the body.

(b)The refractive index will be different in both cases. Refractive index of glass is different for different colours. The speed of blue
    light is less than the speed of red light. So, the wavelength of blue light is less than that of red light. Thus, red light would              deviate less than blue light because of difference in wavelength.

(c)

(d)
   (i) For a given angle of incidence, the prism with higher refractive index produces a greater deviation than the prism which has a         lower refractive index. Thus, the angle of deviation increases with an increase in the refractive index of the medium.
   (ii) The angle of deviation decreases with an increase in the wavelength of light. Thus, a prism deviates violet light the most and          red light the least.

(e)
   (i) Let a1 and a2 be the amplitudes and I1 and I2 be the intensities of the two waves.
   
  (ii) Frequency is the number of waves formed per second. It only depends on time period. Thus, the ratio of their frequencies is           1:1.

Answer 3
(a)The frequency of transverse vibration is given by
    

  where = length of the vibrating string
        T = tension in the string
       m = mass per unit length of the string Therefore, the frequency of transverse vibration of a stretched string can be increased by
  (i) decreasing the length of the string
  (ii) decreasing the radius of the string
  (iii) increasing the tension T in the string

(b)The disturbance produced in the environment because of undesirable loud and harsh sound of level more than 120 dB from the     various sources such as a loudspeaker and moving vehicles is called noise pollution.

(c) For the same change in I, change in V is less for the straight line A than for the straight line B (i.e. the straight line A is less           steep than B). The straight line A represents small resistance, while the straight line B represents more resistance. The equivalent resistance is less in a parallel combination than in a series combination. So, line A represents a parallel combination.

(d)
  (i) Given: I = 400 mA = 400 × 10⁻³ A
    V = 12 V
    V = IR
   

     R =30Ω

(ii) Current drops to I = 320 mA = 320 × 10−3 A
   The music stops playing at
   V = IR
   = 320 × 10^-3× 30
 V= 9.6

(e) Given : R 20 Ω , I 2.5 A
    t =5 minutes = 5 ×60 = 300 s
   Quantit y of heat produced is given as
   H = I^Rt

   = (2.5)² × 20 =300
    H = 37500 J

Answer 4
(a)Two characteristics which a thermionic emitter should possess are
   1. The work function of the substance should be low such that the electrons are emitted from it even when it is not heated to a          very high temperature.
   2. The melting point of the substance should be quite high so that it may not melt when it is heated to the temperature required          for  thermionic emission.

(b)
   
  A = 222 + (4)+ 0
  A = 230
  Z= 85+2(2)+ (-1)
    Z = 88

(c) There will be no change in the nature of radioactivity of the substance. This is because oxidation is a chemical process and does       not involve the nucleus of the substance.

(d)Characteristics required in a material to be used as an effective fuse wire are
   a. High resistivity
   b. Low melting point

(e) In a step-up transformer, the primary coil is made of thicker wire. This is because in a step-up transformer the number of turns      in the secondary coil is more than the number of turns in the primary coil.
   
   E_s > E_p
   But I_s < I_P, i.e. more current flows through the primary coil. Therefore, one must use a thicker wire in the primary coil as              compared to that in the secondary coil.

Answer 5
(a)
  (i) The stone is moving with uniform speed as given in the question.
  (ii) Although the stone is rotating with uniform speed, its direction keeps on changing. Hence, the stone is said to be moving with        uniform acceleration. The direction of acceleration is towards the centre of the circle.
  (iii) The force which acts on the hand is the centrifugal force. Its direction is opposite to the centripetal force, i.e. away from the        centre.

(b)
  (i) The pulley A is a single movable pulley and B is a single fixed pulley.
  (ii) Pulley B is a single fixed type pulley. Its purpose is to change the direction of the effort applied.
  (iii) Effort at C is equal to the load. This is because B is a single fixed pulley and its mechanical advantage is 1. So, we have
      

(c)
   (i) The number of teeth in the driving wheel is n_B = 32 and that in the driven wheel is n_A = 8. Hence, this system is used to  obtain gain in speed.
 
(ii) Load = 120 N; E = 50 N; n = 3
     Mechanical advantage of pulley system is
     
    The efficiency of the system is
     

Answer 6
(a)
  (i) The principle of method of mixtures says that the heat lost by a hot body is equal to the heat gained by a cold body.
  (ii) The other name given to the principle of mixtures is the principle of calorimetry.
  (iii) The principle of mixtures is based on the law of conservation of energy.

(b)The figure for phase change is shown below:

(c) Heat energy lost by the vessel and water contained in it in cooling the water from 50°C to 5°C is used in heating ice to melt it         and then to raise its temperature from 0°C to 5°C.
     Now, heat energy lost by the copper vessel is
    Q_c = m_cc_c Δt= 100 ×0.4× (50 -5)
    Q = 1800 J
   Similarly, heat energy lost by water is
   Q_w = m_wc_w Δt= 150 ×4.2× (50 -5)
   Q = 28350 J
   Hence, the total heat energy lost is
  Q_L =1800+ 28350= 30150 J
  Let m g of ice be used to cool water. So, heat gained by ice is
  Q_I = mL_ice +mc_w Δt
  Q_I = 336m +m× 4.2 ×5 =336m +21m =357m J
  Therefore, from the principle of calorimetry, the mass of ice is
   Q_L =Q_I
   357m= 30150
  30150 m 84.45 g

Answer 7
(a)
   (i) The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant for a given pair of media called          the refractive index.
        

   (ii) When a ray of light enters from one medium to another with different optical densities, it bends because there is a change in          the speed of light in the two media.
   (iii) A ray of light passing from one medium to another does not bend when it is incident normally on the surface.

(b)
   (i) The image formed by the lens is virtual and between the object and the lens. Hence, the lens used is a concave lens.
   (ii) The following image is of formation of the above image:

(c) Scattering is the process of absorption and then re-emission of light energy. The red colour of the white light is scattered the           least, while the violet colour is scattered the most.

Answer 8
(a)
  (i) The waves used for echo depth sounding are ultrasonic waves.
  (ii) Ultrasonic waves are used for echo depth ranging because they can travel undeviated through a long distance.
  (iii) Ultrasonic waves have frequency larger than 20000 Hz. Hence, these waves are not audible to us as the audible range for the          human ear is 20 Hz to 20000 Hz.

(b)
  (i) The sound heard after reflection from a distant obstacle after the original sound has ceased is called an echo.
  (ii) The conditions for an echo to take place are
      a. The minimum distance between the source of sound and the reflector in air must be 17 m.
      b. The size of the reflector must be large enough as compared to the wavelength of sound wave.

(c)
   (i) The phenomenon involved in tuning a radio set to a particular station is called resonance.
   (ii) Resonance: When the frequency of an externally applied periodic force on a body is equal to its natural frequency, the body            readily begins to vibrate with an increased amplitude. This phenomenon is known as resonance.
   (iii) Loudness is the property by virtue of which a loud sound can be distinguished from a faint one, both having the same pitch             and quality.
   (iv) The loudness of sound is measured in phon.

Answer 9
(a)
  (i) Electrons are responsible for current in conductors.
  (ii) The metal case of a geyser should be connected to the Earth wire.
  (iii) The fuse should always be connected to the live wire.

(b)
  (i) A step-up transformer is used in the power transmitting station of a power plant.
  (ii) An alternating current is transmitted from the power station.
  (iii) The current is available to our household at a voltage of 220 V.

(c) E = 12 V; r_i = 2 Ω; R_A = 4 Ω; R_B = 6 Ω
   (i) The current in the circuit is
      

  (ii) The terminal voltage of the cell is
       V = E- Ir_i
        V = 12 - (1 ×2) =12 - 2 = 10 V

  (iii) The potential difference across the 6 Ω resistor is
        V=  IR_R
        V_B =1× 6 = 6 V

  (iv) The electrical energy spent per minute (=60 s) is
        E=  I² Rt
         E = 1² ×4 ×60=  240 J

Answer 10
(a)
  (i) Penetrating power: α, β,γ
  (ii) Ionising power:  γ, β,α
  (iii) Biological effect: α, β,γ

(b)
  (i) In a cathode ray tube, the anode not only accelerates the electrons but also focuses them in a fine energetic beam.
  (ii) In a cathode ray tube, electrical energy is converted to light energy.
  (iii) A cathode ray tube is used to investigate the wave form of an unknown alternating potential by applying it on the Y-plates             and a known periodic time-base potential on the X-plates.

(c)
   (i) In an unstable nucleus, the neutron is changed into a proton by emitting a beta particle. This is represented as
    
  (ii) Elements with the same mass number but different atomic numbers are called isobars.
  (iii)The nucleus of an atom tends to be radioactive when the number of neutrons in the nucleus exceeds the number of protons           inside it.