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PHYSICS
1. A box contains 100mg. of radioactive sample of half - life 270 days. After 540 days,
the mass of radioactive material left will be
(1) 12.5 mg
(2) Zero
(3) 50 mg
(4) 25 mg 2. The magnetic field at the centre of one loop of a circular wire of radius r
carrying current i may be taken as B0. If a particle of charge q passes the centre of a semicircular wire, as shown below, along the axis of the wire, the force on it due to the current
(with v as the particle speed) is.
(1) 1/4 q B0v
(2) q B0 v
(3) zero
(4) 1/2 qB0V 3. A 10 µF capacitor is charged by a battery of e.m.f 100 volts. The
energy stored in the capacitor is
(1) 0.5 mJ
(2) 0.05 mJ
(3) 0.05 J
(4) 0.J 4. As the electron in Bohr orbit of hydrogen atom passes from state n = 2 to n
= 1, the kinetic energy K and the potential energy U change as:
two- fold
(1) K four-fold, U
(2) K two-fold, U four-fold
(3) K two-fold, U also two-fold
(4) K four-fold, U also four-fold. 5. Suppose a tunnel is dug along the diameter of the
earth. A particle is from a point distance h directly above the tunnel. The earth's density is
assumed uniform and the friction is neglected. Then:
particle will be maximum just at the point of release.
(1) The acceleration on the
(2) The particle will drop to the centre of the earth.
(3) The particle will have harmonic oscillation.
(4) The particle will have maximum speed when passing through the centre of the
earth. 6. The door of a domestic refrigerator is kept open while the switch is on, Then the
room will
(1) Get heated for sometime, cooled for sometime
(2) Get neither heated nor cooled
(3) Get heated
(4) Get cooled 7. Which of the following diagrams shows correctly the dispersion of
white light by a prism?
(1)
(2)
(3)
(4)
8. Unpolarised light converts to partially or plane polarised light by many
processes. which of the following does not do that?
(1) Double refraction
(2) Scattering
(3) Reflection
(4) Diffraction. 9. In the circuit below, capacitors A and B have Identical geometry,
but a material of dielectric constant 3 is present between the plates of B. The potential
difference across A and B respectively:
(1) 7.5 V. 2.5 V
(2) 8 V, 2 V
(3) 2.5 V, 7.5 V
(4) 2 V, 8 V 10. Figures below show four ways of making a regular hexagon out of
wires of two different kinds P, Q with current beads at the middle of opposite wires, the
magnetic field at the centre of the hexagon is not zero in:
(1) Case c only
(2) Cases c and d only
(3) Case a only
(4) Case a and b only 11. Just as electricity is supplied at 220 V for domestic use in
India, It is supplied at 110 V in U.S. A. If resistance of 60 W bulb for use in India is R,
that of a 60 W bulb for use in U.S.A. will be:
(1) R
(2) 2R
(3) R/4
(4) R/2 12. Which of the following is correct ?
transverse waves.
(1) Light and solid are both
(2) Coherent source of light passing through two slits causes interference.
(3) Interference of light is evidence for transverse character of light.
(4) Rainbow appears because of scattering of light. 13. Electric current arises from
the flow of charged particles, Now:
negative ions.
(1) In electrolytes, It is mainly due to the flow of
(2) In discharge tubes containing gases at low pressure, it is due to the flow of
positive ions only
(3) In metals, it is mainly due to the flow of electrons.
(4) In semi-conductors, it is mainly due to the flow of holes. 14. Which of the
following demonstrates that earth has a magnetic field?
about the North-South axis.
(1) Earth is a planet rotating
(2) The intensity of cosmic rays (stream of charged particles coming particle coming
from outer space) is more at the poles than at the Equator.
(3) A large quantity of iron-ore is found in the earth.
(4) The earth is surrounded by an ionosphere (a shell of charged particles) 15. In a
nuclear reactor:
(1) Ordinary water moderates the activity of the reactor.
(2) The fuel used is natural uranium which is mostly uranium 235.
(3) The chain reaction is kept under control by rods of cadmium, whose going in
reduces the reaction rate.
(4) The thick concrete shield is used to slow down the speed of neutrons. 16. Given
P = 0.0030 m., Q = 2.40 m and R = 3,000 m., the number of significant figures in P, Q
and R are respectively.
(1) 4, 2, 1
(2) 4, 2, 4
(3) 2, 2, 1
(4) 2, 3, 4 17. A hollow sphere is held suspended, Sand is now poured it in stages,
The centre of gravity of the sphere with the sand:
original position.
(1) First rises and then falls to the
(2) First falls and then rises to the original position.
(3) Rises continuously
(4) Remains unchanged in the process. 18. Shown in the figure is a convergent lens
placed inside a cell filled with a liquid. The lens has a focal length + 20 cm. when in air
and it material has a refractive index 1.50. If the liquid has a refractive index 1.60, the
focal length of the system is:
(1) -24 cm
(2) -100 cm
(3) + 80 cm
(4) - 80 cm 19. In the circuit shown below, every resistance has a value of 24 ohm.
The resistance between terminals P and Q is:
(1) 32 ohm
(2) 42 ohm
(3) 26 ohm
(4) 36 ohm 20. In terms of Rydberg constant R, the shortest wavelength in Balmer
series of hydrogen atom spectrum will have wavelength:
(1) 3/2 R
(2) 9/4 R
(3) 1/R
(4) 4/R 21. Consider the following statements about dimensions : P: Force =
acceleration due to gravity x mass Q :Electric charge = current x time R : Magnetic flux =
Electric voltage x time The correct statements are:
(1) R, P only
(2) P, Q and R
(3) P, Q only
(4) Q, R only 22. The decimal number 53 is equal to the binary number:
11 01
(2) 11 01 01
(3) 11 11 11
(1) 10
(4) 10 10 10 23. The figure represents:
(1) n-p-n transistor
(2) p-n-p transistor
(3) Amplifier
(4) Diode 24. A satellite in a circular orbit of radius R has a period of 4 hours. A
satellite with orbital radius of 4 R around the same planet will have a period :
hours
(1) 32
(2) 64 hours
(3) 8 hours
(4) 16 hours 25. At the mid-point along the length of a long solenoid, the magnetic
field is equal to x, If the length of the solenoid is doubled and the current is reduced to
half, the field at the new mid-point will be nearest to:
(1) x/2
(2) x/4
(3) x
(4) 2x 26. A body thrown upwards reaches a height and comes back. Which of the
following is true about the acceleration due to gravity?
throughout
(1) It remains constant
(2) It varies but never changes sign
(3) It varies continuously with the maximum at the beginning and zero at the top.
(4) It only changes sign when the body is at the top. 27. When light passes from one
medium to another, there is a change in:
(1) Wavelength and velocity
(2) Frequency, wavelength and velocity
(3) Frequency and velocity
(4) Frequency and wavelength. 28. In a mixture of ideal gases, the molecules have
the same:
(1) Mean translational kinetic energy
(2) Root mean square momentum
(3) Speed
(4) Mean speed. 29. An ideal gas has a volume of 3 l at 2 atom pressure. Keeping the
temperature constant, the pressure is doubled. Then the volume of the gas will be:
1.5 l
(2) any value
(3) 3 l
(1)
(4) 6 l 30. The velocity of light in a medium is 2 x 108 m /s. The refractive index of
the medium is:
(1) 1.0
(2) 1.5
(3) 1.4
(4) 2.3 31. Distances of stars is measured in:
(1) Light years
(2) Cosmic kilometer
(3) Stellar mile
(4) Galactic unit 32. Sky seen from earth appears blue because of:
of light
(1) Scattering
(2) Refraction of light
(3) Reflection of light
(4) Polarization of light 33. Optical fibres work on the principle of:
internal reflection
(1) Total
(2) Scattering
(3) Refraction
(4) Reflection 34. A red flower seen through a green glass looks: `
(1) Green
(2) Black
(3) Yellow
(4) Red 35. The relation between velocity (v), frequency (f) and wavelength (is
given by
(1) f = v
2) f = v/
(3) V = f
v = f/ 36. Magnetic lines of force:
(1) Intersect at infinity
(2) Never intersect
(2) Intersect at neutral points
(4) Intersect near through or the south pole. 37. The electric field intensity due to a
hollow charged spherical conductor is maximum:
(1) At any point inside the sphere
(2) Only at the centre of the sphere
(3) Outside the sphere
(4) On the surface of the sphere 38. 1,000 drops of water of radius 1 cm. each
carrying a charge of 10 esu combine to the form a single drop. The capacitance of the
combined drop increases:
(1) 100 times
(2) 1,000 times
(3) 1 time
(4) 10 times. 39. Four resistances of 100 ohm each are connected in the form of a
square. Then the effective resistance along the diagonal points is:
(1) 150 ohms
(2) 100 ohms
(3) 400 ohms
(4) 200 ohms 40. An electron in motion is associated with :
magnetic fields
(1) Both electric and
(2) Either electric or magnetic field
(3) Only an electric field
(4) Only a magnetic field. 41. Two parallel wires carry electric current in the same
direction. The wires:
(1) Do not attract or repel
(2) Oscillate
(3) Attract each other
(4) Repel each other. 42. The direction of force acting on a current carrying
conductor at right angles to a magnetic field is given by:
cork screw rule
(1) Maxwell's right - handed
(2) Ampere's swimming rule
(3) Fleming's left hand rule
(4) Fleming's right hand rule 43. A motor:
magnetic energy
(1) Converts electrical energy into
(2) Creates mechanical energy
(3) Converts electrical energy into mechanical energy
(4) Converts mechanical energy into electrical energy 44. The resistance of an ideal
ammeter is:
(1) Very high
(2) Infinite
(3) Zero
(4) Small 45. Good resistance coils are made of:
(1) Silver
(2) Gold
(3) Manganin
(4) Copper 46. When a metal is heated, its resistance:
(2) May increase or decrease
(1) Remains constant
(3) Increases
(4) Decreases 47. An example of a non-ohmic device is:
(1) Triode
(2) Potentiometer wire
(3) Copper wire
(4) Platinum resistance thermometer. 48. The statement "Algebraic sum of the
currents meeting at a mode is zero" is :
(1) Kirchhoff's law
(2) Faraday's law
(3) Lenz's law
(4) Ampere's law 49. The compensating leads are provided in a platinum resistance
thermometer. This is to:
(1) Provide compensation for the resistance of the leads
(2) Protect the thermometer
(3) Provide fourth arm in the bridge
(4) Compensate for the change in the resistance of the platinum coil. 50. A 4 - v
battery of internal resistance 1 ohm sends a current through a 3- ohm resistor. The
terminal p.d. is:
(1) 0.75 V
(2) 1 V
(3) 1.33 V
(4) 3 V 51. The number of neutrons in a 92U235 nucleus is:
(1) 327
(2) 143
(3) 92
(4) 235 52. When an electron and a position collide:
converted into energy
(1) The mass is not
(2) They Repel each other
(3) The total mass is converted into energy
(4) Part of the mass is converted into energy 53. A diode can be used for:
Rectification
(1)
(2) Detection
(3) Modulation
(4) Amplification 54. The n-type semi-conductor is:
aluminum
(2) Silicon doped with indium.
(3) Germanium doped with arsenic
(1) Germanium doped with
(4) Germanium doped with indium. 55. In a good conductor the energy gap between
the conduction band and valence band is:
(1) Wide
(2) Infinite
(3) Zero
(4) Narrow 56. The rest mass of a photon is:
(1) Dependant on velocity
(2) Zero
(3) Very large
(4) Very small 57. The Avogadro number is:
(1) 6.5 x 10-27
(2) 6.02 x10-23
(3) 6.02 x 1023
(4) 6.25 x 1027 58. The units of Planck's constant are:
(1) Js2
(2) J/s
(3) Js-2
(4) Js 59. In the reaction 1H2 + 1H2 He4 + x, x is:
(1) Neutron
(2) Photon
(3) Proton
(4) Electron 60. The main source of energy in the sun and the stars is:
and fusion reactions
(2) None of the above
(3) Fission reactions
(4) Fusion reactions
(1) Fission