40 physics sample questions for Andhra Pradesh Engineering, Agriculture & Medical (Pharmacy, Veterinary) Common Entrance Test
Ques: Half life of a radioactive substance is T. The time taken for all the nuclei to disintegrate will be
(a) 2T
(b) T2
(c) 4T
(d) Uncertain
Ques. If the uncertainty in the measurement of position of a particle is 1.054 x 10–10 m, then the uncertainty in the measurement of its momentum (in kg-m/s) will be
(a) 10–10
(b) 10–24
(c) 10–30
(d) 10–40
Ques. Two rods of same length and material transfer a given amount of heat in 12 seconds, when they are joined end to end. But when they are joined lengthwise, then they will transfer same heat in same conditions in
(a) 24 seconds
(b) 3 seconds
(c) 1.5 seconds
(d) 48 seconds
Ques. The magnitudes of the gravitational force at distances r1 and r2 from the centre of a uniform sphere of radius R and mass M are F1 and F2 respectively. Then
(a) F1/F2 = r1/r2 if r1 < R and r2 < R
(b) F1/F2 = r12/r22 if r1 > R and r2 > R
(c) F1/F2 = r1/r2 if r1 > R and r2 > R
(d) F1/F2 = r22/r12 if r1 < R and r2 < R
Ques. A candle flame, an electric bulb and a kerosene oil lamp, all produce
(a) Band spectra
(b) Continuous spectra
(c) Line spectra
(d) Absorption spectra
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Ques. The image of an object formed by a plane mirror is
(a) Erect, real and of equal size
(b) Erect, virtual and of equal size
(c) Inverted, real and of equal size
(d) Inverted, virtual and of equal size
Ques. The energy gap in an intansic semiconductor is of the order of
(a) 0.1 eV
(b) 1 eV
(c) 5 eV
(d) 10 eV
Ques. If 2.2 kilowatt power is being transmitted at 44KV on a 20 ohm line, then power loss will be
(a) 0.1 watt
(b) 1.4 watt
(c) 100 watt
(d) 0.05 watt
Ques. NAND gate is the combination of
(a) AND gate and NOT gate
(b) AND gate and OR gate
(c) OR gate and NOT gate
(d) NOT gate and NOT gate
Ques. A plane mirror reflects a pencil of light to form a real image. Then the pencil of light incident on the mirror is
(a) Parallel
(b) Convergent
(c) Divergent
(d) None of the above
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Ques. The shortest wavelength of X-rays emitted from an X-ray tube depends on the
(a) Current in the tube
(b) Voltage applied to the tube
(c) Nature of gas in the tube
(d) Atomic number of target material
Ques. At 0 K, the forbidden gap energy of germanium crystal is about
(a) 1.05 eV
(b) 0.105 eV
(c) 0.72 eV
(d) 0.072 eV
Ques. For proper ventilation of building, windows must be open near the bottom and top of the walls so as to let pass
(a) In more air
(b) In cool air near the bottom and hot air out near the roof
(c) In hot air near the roof and cool air out near the bottom
(d) Out hot air near the roof
Ques. A proton (mass m and charge + e) and an alpha particle (mass 4m and charge + 2e) are projected with the same kinetic energy at right angles to a uniform magnetic field. Which one of the following statements will be true
(a) The alpha-particle will be bent in circular path with a smaller radius that of the proton
(b) The radius of the path of the alpha-particle will be greater than that of the proton
(c) The alpha-particle and the proton will be bent in a circular path with the same radius
(d) The alpha-particle and the proton will go through the field in a straight line
Ques. Water is flowing with a velocity of 3m/s in a pipe of diameter 4 cm. This water enters another tube of diameter 2 cm. The velocity of water in this tube is
(a) 12 m/s
(b) 6 m/s
(c) 3 m/s
(d) 1.5 m/s
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Ques. When the conductivity of a semiconductor is only due to breaking of covalent bonds, the semiconductor is called
(a) Extrinsic
(b) Intrinsic
(c) n-type
(d) p-type
Ques. A tuning fork is sounded with vibrating strings of lengths 0.95m and 1m. It produces 6 beats with each one. The frequency of the tuning fork will be
(a) 150 Hz
(b) 200 Hz
(c) 225 Hz
(d) 234 Hz
Ques. Two equal and opposite charges are placed a certain distance apart and force between them in F. If 20% of charge on one is transferred to another, then the force between them will become
(a) F
(b) 9/16 F
(c) 15/16 F
(d) 16/25 F
Ques. Keeping the temprature of cold junction of a thermocouple as 0°C the thermo-emf is 2mV when the hot juction is at 50°C. On increasing the temprature of hot juction to 100°C the thermo-emf becomes 3.5mV. The temprature of inversion of this thermocouple will be
(a) 225°C
(b) 300°C
(c) 375°C
(d) 450°C
Ques. A closed organ pipe is in unision with a vibrating tuning fork of frequency 264 Hz. If the velocity of sound in air is 330 m/s, then the length of air column will be
(a) 100 cm
(b) 62.50 cm
(c) 93.75 cm
(d) 31.25 cm
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Ques. Two cells of the same emf e but different internal resistances, r1 and r2 are connected in series with an external resistance R. The potential drop across the first cell is found to be zero. The external resistance R is
(a) r1 – r2
(b) r1/r2
(c) r1 r2
(d) r1 + r2
Ques. Hydraulic brakes work on the principal of
(a) Pascal’s Law
(b) Thomson’s Law
(c) Newton’s Law
(d) Bernouli’s Theorem
Ques. The thermions are
(a) Protons
(b) Electrons
(c) Photons
(d) Positrons
Ques. Water is filled into a container with hexagonal cross section of side 6 cm. If the surface tension of water is 0.075 N/m, then the surface energy of water will be
(a) 8.5 x 10–4 Joule
(b) 2.8 x 10–4 Joule
(c) 6.4 x 10–4 Joule
(d) 7 x 10–4 Joule
Ques. After two hours, one-sixteenth of the starting amount of a certain radioactive isotope remained undecayed. The half life of he isotope is
(a) 15 minutes
(b) 30 minutes
(c) 45 minutes
(d) 1 hour
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Ques. An object is placed at a distance of 20 cm, in rarer medium, from the pole of a convex spherical refracting surface of curvature 10 cm. If the refracting index of the rarer medium is 1 and of the refracting medium is 2, then the position of the image is at
(a) (40/3) cm from the pole and inside the denser medium
(b) 40cm from the pole and inside the denser medium
(c) (40/3) cm from the pole and outside the denser medium
(d) 40cm from the pole and outside the denser medium
Ques. Water is filled n a balloon. To what depth of a lake should it be carried in order to decrease its volume by 0.01%. The bulk modulus of elasticity for water is K = 2 x 109 N/m2.
(a) 20.4 meter
(b) 204 meter
(c) 2.04 meter
(d) 2.04 km
Ques. In the interference pattern, energy is
(a) Created at the position of maxima
(b) Destroyed at the position of minima
(c) Conserved but is redistributed
(d) None of the above
Ques. A coil has 20 turns and area of each turn is 0.2 m2. If the plane of the coil makes an angle of 60° with the direction of magnetic field of 0.1 tesla, then the magneticflux associated with the coil will be
(a) 0.4 weber
(b) 0.346 weber
(c) 0.2 weber
(d) 0.02 weber
Ques. A bus and a jeep are moving with same kinetic energy. Equal retarding forces are applied to both with the help of brakes. The distances covered by them before coming to rest will be
(a) More by jeep
(b) More by bus
(c) Equal by both
(d) Dependent upon the mass of jeep or bus
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Ques. A piston of cross-section area 100 cm2 is used in a hydraulic press to exert a force of 107 dynes on the water. The cross-sectional area of the other piston which supports an object having a mass 2000 kg. is
(a) 100 cm2
(b) 109 cm2
(c) 2 x 104 cm2
(d) 2 x 1010 cm2
Ques. In a junction diode the direction of diffusion current is
(a) From P-region to N-region
(b) From N-region to P-region
(c) From P-region to N-region if the junction is forward biased and vice versa if junction is reverse biased
(d) From N-region to P-region if the junction is forward biased and vice versa if it is reverse biased
Ques. The image of a star (effectively a point source) is made by convergent lens of focal length 50 cm and diameter of aperture 5.0 cm. If the lens is ideal and the effective wavelength in image formation is taken as 5 x 10–5 cm, the diameter of the image formed will be nearest to
(a) Zero
(b) 10–6 cm
(c) 10–5 cm
(d) 10–3 cm
Ques. A biconvex lens forms a real image of an object placed perpendicular to its principal axis. Suppose the radii of curvature of the lens tend to infinity. Then the image would
(a) Disappear
(b) Remain as real image still
(c) Be virtual and of the same size as the object
(d) Suffer from aberrations
Ques. Gauss’s law is true only if force due to a charge varies as
(a) r–1
(b) r–2
(c) r–3
(d) r–4
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Ques. According to corpuscular theory of light, the different colours of light are due to
(a) Different electromagnetic waves
(b) Different force of attraction among the corpuscles
(c) Different size of the corpuscles
(d) None of the above
Ques. The bending of beam of light around corners of obstacles is called
(a) Reflection
(b) Diffraction
(c) Refraction
(d) Interference
Ques. A radio station is transmitting waves of wavelength 300 m. If the radiating power of the transmitter is 10 KW, then the number of photons emitted per second will be
(a) 1.5 x 1035
(b) 1.5 x 1031
(c) 1.5 x 1029
(d) 1.5 x 1033
Ques. In Young’s double slit experiment the fringe width on a distance screen is 1°. If the ‘wavelength’ of light is 6000Å then the distance between two slits will be
(a) 0.34 mm
(b) 0.034 mm
(c) 34 mm
(d) 340 mm
Ques. In a nuclear reactor cadmium rods are used for
(a) Neutron emission
(b) Absorption unnecessary neutrons
(c) Absorption of heat
(d) Reducing the velocity of neutrons
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Ques. A nucleon is confined within a nucleus of radius 10–14 m The minimum uncertainty in its momentum will be (in kg-m/s)
(a) 2.15 x 10–20
(b) 5.27 x 10–21
(c) 3.9 x 10–27
(d) 8.6 x 1019
Ques. Through which character we can distinguish the light waves from sound waves
(a) Interference
(b) Refraction
(c) Polarisation
(d) Reflection
Ques. Semiconductor is damaged by the strong current due to
(a) Lack of free electron
(b) Excess of electrons
(c) Excess of proton
(d) None of these
Ques. Wave which cannot travel in vacuum is
(a) X-rays
(b) Infrasonic
(c) Ultraviolet
(d) Radiowaves
Ques. Fermi level of energy of an intrinsic semiconductor lies
(a) In the middle of forbidden gap
(b) Below the middle of forbidden gap
(c) Above the middle of forbidden gap
(d) Outside the forbidden gap
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Ques. When electron beam passes through an electric field, they gain kinetic energy. If the same beam passes through magnetic field, then
(a) Their energy increases
(b) Their momentum increases
(c) Their potential energy increases
(d) Energy and momentum both remains unchanged
Ques. When the angle between the lines joining the first and nth HPZ increases then the obliquity factor
(a) Decreases
(b) Increases
(c) Remains unchanged
(d) Becomes zero
Ques. In a discharge tube at 0.02 mm, there is a formation of
(a) FDS
(b) CDS
(c) Both space
(d) None of these
Ques. The idea of matter waves was given by
(a) Davisson and Germer
(b) de-Broglie
(c) Einstein
(d) Planck
Ques. If intensity of incident light is increased in PEE then which of the following is true
(a) Maximum K.E. of ejected electron will increase
(b) Work function will remain unchanged
(c) Stopping potential will decrease
(d) Maximum K.E. of ejected electron will decrease
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Ques. To get three images of a single object, one should have two plane mirrors at an angle of
(a) 30°
(b) 60°
(c) 90°
(d) 150°
Ques. Two tuning forks of frequencies 380 Hz and 384 Hz are sounded together to produce beats. What will be the time interval between consecutive maximum and minimum intensity
(a) ½ s
(b) ¼ s
(c) 1/8 s
(d) 1/16 s
Ques. According to Bohr’s theory of the hydrogen atom, the diameter of the first orbit is about
(a) 0.1 Å
(b) 1 Å
(c) 13.6 Å
(d) 5890 Å
Ques. Quantam nature of light is explained by which of the following phenomenon
(a) Huygen wave theory
(b) Photoelectric effect
(c) Maxwell electromagnetic theory
(d) de-Broglie theory
Ques. The frequency of transmission of a radio station is 300 MHz. The wavelength of the waves transmitted by the centre will be
(a) 5 m
(b) 10 m
(c) 15 m
(d) 20 m
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Ques. When ice and wax melt at their normal melting point?
(a) Internal energy of both ice and wax increases
(b) Internal energy of both ice and wax decreases
(c) Internal energy of ice increases and that of wax decreases
(d) Internal energy of ice decreases and that of wax increases
Ques. A cyclotron oscillator frequency is 1MHz. What should be the operating magnetic field for accelerating protons
(a) 0.656 T
(b) 0.565 T
(c) 0.655 T
(d) 0.556 T
