Physics — Suggested Paper 3

1(i). A metallic wire is stretched in such a way that its new length becomes twice the original length. How does its specific heat capacity change? (a) becomes double (b) becomes 4 times (c) becomes 1⁄4 times (d) remains the same

1(ii). Assertion (A) : Tiny air molecules scatter blue light more than red light. Reason (R) : The refractive index of a medium is greater for blue light than red light. (a) (A) is true but (R) is false. (b) (A) is false but (R) is true. (c) Both (A) and (R) are true and (R) is correct explanation of (A). (d) Both (A) and (R) are true and (R) is not the correct explanation of (A).

1(iii). Which one of the following is the correct mathematical relation? (a) Power = Force/ Velocity (b) Power = Force x Acceleration (c) Power Force/ Acceleration (d) Power= Force x Velocity

1(iv). Which one of the following diagnostic methods use reflection of sound? (a) CT scan (b) Electrocardiogram (c) Echo cardiogram (d) MRI

1(v). The graph plotted for potential difference (V) against current (I) for ohmic resistors is : (a) A curve passing through the origin. (b) A straight line not passing through origin. (c) A straight line passing through the origin. (d) A circle centred at the origin.

1(vi). A ray of light is incident normally on a face of an equilateral prism. The ray gets totally reflected at the second refracting surface. The total deviation produced in the path of the ray is: (a) 30° (b) 60° (c) 90° (d) 120°

1(vii). Clockwise moment produced by a force about a fulcrum is considered to be: (a) Positive (b) Negative (c) Zero (d) None of these

1(viii). The Velocity Ratio (VR) of a block and tackle system of two pulleys with the effort in the upward direction is: (a) 1 (b) 2 (c) 3 (d) 4

1(ix). An atom of lithium contains 3 electrons, 3 protons and 4 neutrons. Its mass number is: (a) 3 (b) 4 (c) 7 (d) 10

1(x). For a real image formed by a convex lens, the ratio of I : O = 2 : 5, then the object is: (I is the height of the image and O is the height of the object) (a) between O and F (b) beyond 2F (c) at F (d) between F and 2F

1(xi). The following figure shows a small bar magnet falling freely through a copper ring. For the observer at A, the direction of the induced current will be : (a) clockwise when magnet is above and below the ring (b) anticlockwise when magnet is above and below the ring (c) anticlockwise when magnet is above the ring and clockwise when the magnet is below the ring (d) clockwise when magnet is above the ring and anticlockwise when the magnet is below the ring

1(xii). If water absorbs 4000 joule heat to increase the temperature of 1 kg water through 1°C then the specific heat capacity of water is : (a) 4 Jkg-1°C-1 (b) 400 Jg-1°C-1 (c) 4 Jg-1°C-1 (d) 4.2 Jg-1°C-1

1(xiii). Assertion (A) : Ultraviolet radiations are scattered more as compared to the microwave radiations. Reason (R) : Wavelength of ultraviolet radiation is more than the wavelength of microwave radiation. (a) Both A and R are true. (b) A is true but R is false. (c) A is false but R is true. (d) Both A and R are false.

1(xiv). 1 joule= __________ erg (a) 10^9 (b) 10^7 (c) 10^5 (d) 10^6

1(xv). When the stem of vibrating tuning fork is pressed on a table, the tabletop starts vibrating. These vibrations are definitely an example of: (a) resonance (b) natural vibrations (c) forced vibrations (d) damped vibrations

2(i)(a). In uniform circular motion the centrifugal force acts ............... [towards the centre/away from the centre/along the tangential direction].

2(i)(b). Refractive index of a medium is independent of ............... [temperature/angle of incidence/wavelength of light].

2(i)(c). Heat absorbed during change of phase depends on ............... [mass/change in temperature/specific heat capacity] of the substance.

2(i)(d). Emf of a cell is ............... [greater than/less than/equal to] the terminal voltage when the cell is in open circuit.

2(i)(e). In a step-up transformer the turns ratio is ............... [more than 1/ less than 1/ equal to 1].

2(i)(f). The nuclear radiation with lowest ionising power is ............... [α/β/γ].

2(ii)(i). The heat capacity of the body is 60 J K-1.

2(ii)(ii). The specific heat capacity of lead is 130 J kg-1 K-1

2(iii). If the power of a motor be 100 kW, at what speed can it raise a load of50,000 N?

3(i). A nucleus ₈₄X²⁰² of an element emits an alpha particle followed by a beta particle. The final nucleus is ₐYᵇ. Find a and b.

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

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

3(iv)(i). Why is the ratio of the velocities of light of wavelengths 4000 Å and 8000 Å in vacuum 1 : 1 ?

3(iv)(ii). Which of the above wavelengths has a higher frequency?

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

3(vi)(i). The work done by them.

3(vi)(ii). The power developed by them.

3(vii)(a). When does the nucleus of an atom tend to become radioactive?

3(vii)(b). Name a single pulley in which displacement of load and effort is not the same.

3(vii)(c). State one advantage of this pulley.

4(i)(a). State whether the conductor used is ohmic or non-ohmic.

4(i)(b). Justify your answer.

4(i)(c). State Ohm’s law.

4(ii)(a). Identify the type of transformer.

4(ii)(b). In this type of transformer which of the wire is thicker, the primary or the secondary? Give a reason.

4(iii)(a). Calculate the total resistance of the circuit.

4(iii)(b). Calculate the current drawn from the cell.

4(iii)(c). State whether the current through 10 Ω resistor is greater than, less than or equal to the current through the 12 Ω resistor.

5(i)(a). Name the waves used in SONAR.

5(i)(b). In the above diagram Lata stands between two cliffs and claps her hands. Determine the time taken by her to hear the first echo. Speed of sound in air = 320 m s⁻¹.

5(ii)(a). Complete the following radioactive reaction: X → Y + ⁴₂He → ²³⁴₉₁Z + ⁰₋₁e

5(ii)(b). Uranium is available in two forms U-235 and U-238. Which of the two isotopes of Uranium is more fissionable?

5(iii)(a). Name the phenomenon illustrated by the above experiment.

5(iii)(b). Why is a loud sound heard at this particular length?

5(iii)(c). If the present tuning fork is replaced with a tuning fork of higher frequency, should the length of the air column increase or decrease to produce a loud sound? Give a reason.

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.

6(b)(i). Name the type of lens which forms the above image.

6(b)(ii). Draw a ray diagram to show the formation of the image with the above stated characteristics.

6(c)(i). What is the nature of the image so formed ?

6(c)(ii). Calculate the distance of the image from the lens.

6(c)(iii). Calculate the magnification of the image.

7(a)(i). Name the colour code of the wire which is connected to the metallic body of an appliance.

7(a)(ii). Draw the diagram of a dual control switch when the appliance is switched ‘ON’.

7(b)(i). Which particles are responsible for current in conductors ?

7(b)(ii). To which wire of a cable in a power circuit should the metal case of a geyser be connected ?

7(b)(iii). To which wire should the fuse be connected ?

7(c)(i). Explain the meaning of the statement ‘current rating of a fuse is 5A’.

7(c)(ii). In the transmission of power the voltage of power generated at the generating stations is stepped up from 11 kV to 132 kV before it is transmitted. Why ?

8(a)(i). Define Calorimetry.

8(a)(ii). Name the material used for making a Calorimeter.

8(a)(iii). Why is a Calorimeter made-up of thin sheets of the above material answered in (ii) ?

8(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.

8(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 J g-1 °C-1; Specific latent heat of fusion of ice = 336 J g-1; Specific heat capacity of copper = 0.4 J g-1 °C-1 ]

9(a)(i). Derive a relationship between S.I. and C.G.S. unit of work.

9(a)(ii). A force acts on a body and displaces it by a distance S in a direction at an angle θ with the direction of force. What should be the value of θ to get the maximum positive work?

9(b)(i). Which of the two forces acting on the rigid rod causes clockwise moment?

9(b)(ii). Is the rod in equilibrium?

9(b)(iii). The direction of 20 gf force is reversed. What is the magnitude of the resultant moment of the forces on the rod?

9(c)(i). Draw a diagram to show a block and tackle pulley system having a velocity ratio of 3 marking the direction of load (L), effort (E) and tension (T).

9(c)(ii). The pulley system drawn lifts a load of 150 N when an effort of 60 N is applied. Find it's mechanical advantage.

9(c)(iii). Is the above pulley system an ideal machine or not?