Section I is compulsory. Attempt any four questions from Section II.
Section (40 Marks)
Attempt all questions from this Section
(a) The diagram below shows a claw hammer used to remove a nail:
- To which class of lever does it belong?
- Give 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. 
- Name the physical quantity which is measured in calories.
- How is calorie related to the S.I unit of that quantity? 
- Define couple.
- State the S.I. unit of moment of couple. 
- Define critical angle.
- State one important factor which affects the critical angle of a given medium. 
(a) An electromagnetic radiation is used for photography in fog.
- Identify the radiation.
- Why is this radiation mentioned by you, ideal for this purpose? 
- What is the relation between the refractive index of water with respect to air (aµw) and the refractive index of air with respect to water (wµa).
- If the refractive index of water with respect to air (aµw) is 5/3. Calculate the refractive index of air with respect to water (wµa). 
(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 holes near his mouth, will the pitch of the note produced, increase or decrease? Give a reason. 
(e) The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42º. Complete the path of the ray PQ till it emerges out of the block. [Write necessary angles.] 
- If the lens is placed in water instead of air, how does its focal length change?
- 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:
- intensities and
- frequencies? 
(c) How does an increase in the temperature affect the specific resistance of a:
- Metal and
- Semiconductor? 
- Define resonant vibrations.
- Which characteristic of sound, makes it possible to recognize a person by his voice without seeing him? 
(e) Is it possible for a hydrogen (11H) nucleus to emit an alpha particle? Give a reason for your answer. 
(a) Calculate the effective resistance across AB: 
- State whether the specific heat capacity of a substance remains the same when its state changes from solid to liquid.
- Give 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
x < y. [x and y are magnitudes of deflection.] 
- Why is a nuclear fusion reaction called a thermo nuclear reaction?
- Complete the reaction: 3He2 + 2H1 → 4He2 + …………… + Energy 
(e) State two ways to increase the speed of rotation of a D.C. motor. 
Section (40 Marks)
Attempt any four questions from this Section
(a) A body of mass 10 Kg is kept at a height of 5 m. It is allowed to fall and reach the ground.
- What is the total mechanical energy possessed by the body at the height of 2 m assuming it is a frictionless medium?
- What is the kinetic energy possessed by the body just before hitting the ground? Take g = 10 m/s2. 
(b) A uniform meter scale is in equilibrium as shown in the diagram:
- Calculate the weight of the meter scale.
- 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 shows a pulley arrangement:
- Copy the diagram and mark the direction of tension on each strand of the string.
- What is the velocity ratio of the arrangement?
- If the tension acting on the string is T, then what is the relationship between T and effort E?
- If the free end of the string moves through a distance x, find the distance by which the load is raised. 
(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.
- Name the type of lens which forms the above image.
- Draw a ray diagram to show the formation of the image with the above stated characteristics. 
(c) An object is placed at a distance 24 cm in front of a convex lens of focal length 8 cm.
- What is the nature of the image so formed?
- Calculate the distance of the image from the lens.
- Calculate the magnification of the image. 
(a) It is observed that during march-past we hear a base drum distinctly from a distance compared to the side drums.
- Name the characteristic of sound associated with the above observation.
- Give 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 the 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.
- Name the type of oscillation, C will execute.
- Name the type of oscillation, D will execute.
- If the length of D is made equal to C then what difference will you notice in the oscillations of D?
- What is the name of the phenomenon when the length of D is made equal to C? 
- Write one advantage of connecting electrical appliances in parallel combination.
- What characteristics should a fuse wire have?
- 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.
- Copy the diagram and complete it so that the bulb is switched ON.
- Out of A & B which one is the live wire and which one is the neutral wire? 
The diagram above shows a circuit with the key k open. Calculate:
- the resistance of the circuit when the key k is open.
- the current drawn from the cell when the key k is open.
- the resistance of the circuit when the key k is closed.
- the current drawn from the cell when the key k is closed. 
- Define Calorimetry.
- Name the material used for making a Calorimeter.
- 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 42 g. When a certain mass of ice at 0°C is added to it, the final steady 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 = 336 Jg-1; Specific heat capacity of copper = 0.4 Jg-1°C-1] 
(a) Draw a neat labeled diagram of an A.C. generator. 
Define nuclear fission.
Rewrite and complete the following nuclear reaction by filling in the atomic number of Ba and mass number of Kr: 23592𝑈 + 01𝑛 → 144...𝐵𝑎 + ...36𝐾𝑟 + 3 01𝑛 + 𝐸𝑛𝑒𝑟𝑔𝑦 
(c) The diagram below shows a magnetic needle kept just below the conductor AB which is kept in North South direction.
- In which direction will the needle deflect when the key is closed?
- Why is the deflection produced?
- What will be the change in the deflection if the magnetic needle is taken just above the conductor AB?
- Name one device which works on this principle.