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# Question Paper (Section wise)

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Question 1
Positive Marks: 4 / Negative Marks: 1
•  1) A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4m long, when the resistance R, connected across the given cell, has values of. (i) Infinity          (ii) 9.5 Ω The balancing lengths’, on the potentiometer wire are found to be 3m and 2.85 m, respectively. The value of internal resistance of the cell is.
1. 0.25 Ω

2. 0.95 Ω

3. 0.5 Ω

4. 0.75 Ω

•  2) Following figures show the arrangement of bar magnetism in different configurations. Each magnet has magnetic dipole moment  . Which configuration has highest net magnetic dipole moment?
1. (a)

2. (b)

3. (c)

4. (d)

•  3) In an ammeter 0.2 % of main current passes through the galvanometer. If resistance of galvanometer is G, the resistance ammeter will be-
•  4) Two identical long conducting wires AOB and COD are placed at right angle to each other, with one above other such that ‘O’ their common point for the two. The wires carry I1 and I2 currents respectively. Point ‘P’ is lying at distance ‘d’ from ‘O’ along a direction perpendicular to the plane containing the wires. The magnetic field at the point ‘P’ will be-
•  5) A thin semicircular conducting ring (PQR) of radius ‘r’ is falling with its plane vertical in a horizontal magnetic field B/ as shown in figure. The potential difference developed across the ring when its speed is v, is-
1. zero

2. Bvπr2/2 and P is at higher potential

3. πrBv and R is at higherpotential

4. 2rBv and R is at higher potential

•  6) A transformer having efficiency of 90% is working on 200V and 3kW power supply. If the current in the secondary coil is 6A, the voltage across the secondary coil and the current in the primary coil respectively are –
1. 300 V, 15 A

2. 450 V, 15 A

3. 450 V, 13.5 A

4. 600 V, 15 A

•  7) Light with an energy flux of 25 × 104 Wm-2 falls on a perfectly reflecting surface at normal incidence. If the surface area is 15 cm2, the average force exerted on the surface is –
1. 1.25 × 10-6 N

2. 2.50 × 10-6 N

3. 1.20 × 10-6 N

4. 3.0 × 10-6 N

•  8) A beam of light of λ = 600 nm from a distance source falls on a single alit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between first dark fringes on either side of the central bright fringe is –
1. 1.2 cm

2. 1.2 mm

3. 2.4 cm

4. 2.4 mm

•  9) In the Young’s double-slit experiment, the intensity of light at a point on the screen where the path difference is λ is K, (λ being the wave length of light used). The intensity at a point where the path difference is λ/4, will be –
1. K

2. K/4

3. K/2

4. Zero

•  10) The condition under which a microwave oven heats up a food item containing water molecules most efficiently is-
1. Infra-red waves produce heating in a microwave oven

2. The frequency of the microwaves must match the resonant frequency of the water molecules

3. The frequency of the microwaves has no relation with natural frequency of the water molecules

4. Microwaves are heat waves, so always produce heating

•  11) An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 ms-1 and the second part of mass 2Kg moves with 8 ms-1 speed. If the third part files off with 4 ms-1 speed, then its mass is-
1. 17 kg

2. 3 kg

3. 5 kg

4. 7 kg

•  12) In an experiment four quantities a, b, c and d are measured with percentage error 1%, 2%, 3% and 4% respectively. Quantity P is calculated as follows  error in P is
1. 4 %

2. 14 %

3. 10 %

4. 7 %

•  13) A small object of uniform density rolls up a curved surface with an initial velocity ‘v’. It reaches up to a maximum heights of  with respect to the initial position. The object is
1. Disc

2. Ring

3. Solid sphere

4. hollow sphere

•  14) A Plano convex lens fits exactly into a Plano concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices µ1 and µ2 and R is the radius of curvature of the curved surface of the lenses, then the focal length of combination is –
•  15) A parallel beam of fast moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statements is correct?
1. The angular width of central maximum will be unaffected

2. Diffraction pattern is not observed on the screen in the case of electrons

3. The angular width of the central maximum

4. The angular width of the central maximum will decrease

•  16) For a normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens behind the cornea is 20 D. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be –
1. 1.5 cm

2. 5 cm

3. 2.5 cm

4. 1.67 cm

•  17) The upper half of an inclined plane of inclination θ is perfectly smooth while lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and lower half of the plane is given by –
1. µ = tan θ

2. µ =2 tan θ

•  18) A wave travelling in the +ve x-direction having displacement along y-direction as 1 m, wavelength 2πm and frequency of   Hz is represented by:
1. y = sin (2πx + 2πt)

2. y = sin (x - 2t)

3. y = sin (2πx - 2πt)

4. y = sin (10πx + 20πt)

•  19) What is the flux through a cube of side ‘a’ if a point charge of q is at one of its corner?
•  20) An electrical dipole of moment ‘p’ is placed in an electric field of intensity ‘E’. The dipole acquires a position such that the axis of the dipole makes an angle Ѳ with the direction of the field. Assuming that the potential energy of the dipole to be zero when Ѳ = 90°, the torque and the potential energy of the dipole will respectively be:-
1. p E sin Ѳ, 2p E cos Ѳ

2. p E sin Ѳ, -p E cos Ѳ

3. p E sin Ѳ, -p E cos Ѳ

4. p E sin Ѳ, -2p E cos Ѳ

•  21) Four point charges -Q, -q, 2q and 2Q are placed, one at each corner of the square. The relation between Q and q for which the potential at the centre of the square is zero is:
1. Q = q

2. Q = -q

•  22) A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It:
1. will stay in north-south direction only

2. will stay in east-west direction only

3. will become rigid showing no movement

4. will stay in any position

•  23) A millivoltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohm) of necessary shunts will be:
1. 1 Ω

2. 0.05 Ω

3. 0.001 Ω

4. 0.01 Ω

•  24) Two similar coils of radius R are lying concentrically with their planes at right angles to each other. The currents flowing in them are I and 21 respectively. The resultant magnetic field induction at the centre will be:
•  25) Alternating electric field of frequency v, is applied across the dees (radius = R) of a cyclotron that is being used to accelerate protons (mass = m). The operating magnetic field (B) used in the cyclotron and the kinetic energy (K) of the proton beam, produced by it, are given by:
•  26) The magnifying power of a telescope is 9. When it is adjusted for parallel rays the distance between the objective and eyepiece is 20 cm. The focal length of lenses are:
1. 18 cm, 2 cm

2. 11 cm, 9 cm

3. 10 cm, 10 cm

4. 15 cm, 5 cm

•  27) A ray of light is incident at an angle of incidence, I, on one face of a prism of angle A (assumed to be small) and emerges normally from the opposite face. If the refractive index of the prism is μ, the angle of incident I, is nearly equal to:
1. A/ μ

2. A/2 μ

3. μA

•  28) The half-life of a radioactive nucleus is 50 days. The time interval (t2 – t1) between the time t2 when  of it has decayed and time t1 when t1 when   of it had decayed is -
1. 60 days

2. 15 days

3. 30 days

4. 50 days

•  29) A rod length 10 cm lies along the principle axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is-
1. 2.5 cm

2. 5 cm

3. 10 cm

4. 15 cm

•  30) Two radiation of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is-
1. 1 : 1

2. 1 : 5

3. 1 : 4

4. 1 : 2

•  31) Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 × 10-2 C and 5 × 10-2 C respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is-
1. 4 × 10-2 C

2. 1 × 10-2 C

3. 2 × 10-2 C

4. 3 × 10-2 C

•  32) A cell having an emf ɛ and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by-
•  33) For the angle of minimum deviation of a prism to be equal to its refracting angle, the prism must be made of a material whose refractive index-
1. is less than 1

2. is grater than 2

3. lies between   and 1

4. lies between 2 and

•  34) A circular platform is mounted on a frictionless vertical axle. Its radius R = 2m and its moment of inertia about the axle is 200 kg m2. It is initially at rest. A 50 kg man stands on the edge of the platform and begins to walk along the edge at the speed of 1 ms-1 relative to the ground. Time taken by the man to complete one revolution is-
1. 2π s

2. π s

•  35) A slab of stone of area 0.36 m2 and thickness 0.1 m is exposed on the lower surface to steam at 100°C. A block of ice at 0°C rests on the upper surface of the slab. In one hour 4.8 kg of ice is melted. The thermal conductivity of slab is: (Given latent heat of fusion of ice 3.36 × 105 J kg-1)
1. 2.05 J/m/s/°C

2. 1.02 J/m/s/°C

3. 1.24 J/m/s/°C

4. 1.29 J/m/s/°C

•  36) The dimension of (μ0ε0)-1/2 are-
1. [L-1T]

2. [LT-1]

•  37) A biconvex lens has a radius of curvature of magnitude 20cm. Which one of the following options describe best the image formed of an object of height 2 cm placed 30 cm from the lens?
1. Real, inverted, height = 1 cm

2. Virtual, upright, height = 1 cm

3. Virtual, upright, height = 0.5 cm

4. Real, inverted, height = 4 cm

•  38) In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is-
1. 2.3 V

2. 1.8 V

3. 1.3 V

4. 0.5 V

•  39) Electrons used in an microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 km then the de- Broglie wavelength associated with the electrons would-
1. Increases by 4 times

2. Increase by 2 times

3. Decrease by 2 times

4. Decrease by 4 times

•  40) Light of two different frequencies whose photons have energies 1eV and 2.5eV respectively illuminated metallic surface whose work function is 0.5 eV successively. Ration of maximum speeds of emitted electrons will be
1. 1 : 5

2. 1 : 4

3. 1 : 2

4. 1 : 1

•  41) In the Davision and Germer experiment, the velocity of electrons emitted from the electron gun can be increases by-
1. Decreasing the potential difference between the anode the filament

2. Increasing the potential difference between the anode and filament

3. Increasing the filament current

4. Decreasing the filaments current

•  42) The half -life of a radioactive isotope X is 50 years. It decays to another element Y which is stable. The two elements X and Y were found to be in the ratio of 1: 15 in a sample of a given rock. The age of the rock was estimated to be-
1. 100 years

2. 150 years

3. 200 years

4. 250 years

•  43) Photoelectric emission occurs only when the incident light has more than a certain minimum-
1. Frequency

2. Power

3. Wavelength

4. Intensity

•  44) Fusion reaction takes place at high temperature because
1. Molecules break up at high temperature

2. Nuclei break up at high temperature

3. Atoms get ionized at high temperature

4. Kinetic energy is high enough to overcome the coulomb repulsion between nuclei

•  45) A nucleus  emits one α particle and two β particles. The resulting nucleus is-
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