CBSE Class 11 Physics MCQs Set 3

Question. A current of 5 A passes along a wire of length 1.0 m. the wire is at right angles to a magnetic field of flux density of 0.15 T. The force acting on the wire is...
A. 0
B. 0.03 N
C. 0.75 N
D. 33 N
Answer: C

Question. The end product of most radioactive decay series is usually some form of
A. carbon
B. helium
C. hydrogen
D. lead
Answer: D

Question. The cause of surface tension is...
A. adhesive forces
B. cohesive forces
C. external forces
D. gravitational force
Answer: B

Question. The unit 'poise' is...
A. dyne.sec/cm²  
B. dyne.cm/sec²  
C. newton.sec/m²  
D. dyne.sec/cm
Answer: A

Question. Emission line spectrum will be obtained from...
A. candle flame
B. sodium lamp
C. Sun
D. white hot filament of an electric bulb
Answer: B

Question. A hollow insulated brass sphere is positively charged. The electric potential inside the sphere is...
A. zero
B. greater than the potential at the surface
C. smaller than the potential at the surface
D. the same as that on the surface
Answer: D

Question. The linear momentum of a body is P = a + (bt²/2). The force acting on the body is...
A. a + (bt/2)
B. a + bt
C. bt/2
D. bt
Answer: D

Question. The weight of a body on the surface of earth is 100 N. Its weight at a depth half way to the centre of earth will be...
A. 50 N
B. 100 N
C. 25 N
D. 125 N
Answer: A

Question. Two wires C and D of the length in the ratio 2 : 3, diameter in the ratio 2 : 3 and of the same material, are subjected to same force. Then the ratio of their extensions lc : ld is...
A. 3 : 2
B. 2 : 3
C. 4 : 9
D. 8 : 27
Answer: C

Question. The potential energy of a harmonic oscillator is maximum when the displacement is equal to...
A. zero
B. 1/2 amplitude
C. amplitude
D. 1/4 amplitude
Answer: C

Question. When the forces acting on a body are in equilibrium, its...
A. velocity is zero
B. displacement is zero
C. acceleration is zero
D. momentum is zero
Answer: C

Question. An object at rest may possess...
A. velocity
B. momentum 
C. kinetic energy 
D. potential energy
Answer: D

Question. A nonconservative force does not give rise to...
A. thermal energy
B. kinetic energy
C. light energy
D. potential energy
Answer: D

Question. Atoms forming a molecule attain the arrangement in which they obtain...
A. zero potential energy
B. minimum potential energy
C. maximum potential energy
D. none of the above
Answer: B

Question. Bulk modulus of a liquid is...
A. higher than that for a solid
B. higher than that for a gas
C. lower than that for a gas
D. zero
Answer: B

Question. The CGS unit of coefficient of viscosity is...
A. dyne.second/cm²
B. newton.second/cm² 
C. dyne.(second)2/cm² 
D. newton.second/cm
Answer: A

Question. The volume of a gas sample is directly proportional to its...
A. Fahrenheit temperature
B. Celsius temperature
C. Kelvin temperature
D. pressure
Answer: C

Question. The approximate relationship between the coefficient of linear expansion(α) and the coefficient of cubical expansion(γ) is...
A. γ = α²
B. γ = α³
C. α = 3 γ
D. γ = 3 α
Answer: D

Question. When capacitors are in parallel...
A. they are all at the same potential
B. they are at different potentials
C. their capacitances are equal
D. the equivalent capacitance is zero
Answer: A

Question. The earth's magnetic field at sea level is...
A. 3 x 10^-9 T
B. 3 x 10⁹ T
C. 3 x 10^-5 T
D. 3 x 10⁵ T
Answer: C

Question. Monoatomic gases give...
A. line spectra
B. band spectra
C. continuous spectra
D. line and band spectra
Answer: A

Question. The centre of mass of a rigid body...
A. lies inside the body
B. lies outside the body
C. can be inside or outside of the body
D. may not exist
Answer: C

Question. If 'l' is the length of a simple pendulum and 'T' its period, then 'g' is given by...
A. (4π²l)/T²
B. 2π/(√ l/t)
C. 2πl/t
D. (4πl²)/t²
Answer: A

Question. The rate at which an object radiates electromagnetic energy does not depend on its...
A. surface area
B. mass
C. temperature
D. ability to absorb radiation
Answer: B

Question. Which of the following is neither a basic physical law nor derivable from one?
A. Coulomb's law
B. Ohm's law
C. Kirchhoff's first law
D. Kirchhoff's second law
Answer: B

Question. The power dissipated as heat in an a.c. circuit depends on its...
A. resistance
B. inductive reactance
C. capacitive reactance
D. impedance
Answer: A

Question. Impedance is a maximum at resonance in...
A. a series RLC circuit
B. a parallel RLC circuit
C. all RLC circuits
D. no RLC circuit
Answer: B

Question. Red shift indicates...
A. recession of star
B. approaching movement of star
C. that red light changes to violet
D. that violet light changes to red
Answer: A

Question. The penetration power of beta particles is 1. Then the relative penetration power of gamma rays is...
A. 1
B. 100
C. 1/1000
D. 1000
Answer: B

Question. In a common-base circuit the current gain is...
A. 0
B. 1
C. greater than 1
D. smaller than 1
Answer: D

Question. The error in measuring the radius of a sphere is 2%. Then the error in the measurement of its volume is...
A. 8%
B. 6%
C. 2%
D. 9%
Answer: B

Question. A magician is throwing rings into air in such a way that when a ring is at its maximum height he throws another ring. If the time difference between each throw is 1 sec then the height attained by the ring is...
A. 49 m
B. 49 cm
C. 9.8 m
D. 4.9 m
Answer: D

Question. If the mass and force are doubled then the acceleration will...
A. double
B. become thrice
C. become four time
D. remain same as before
Answer: D

Question. A string is tied to the neck of a bottle containing soda water and then whirled in a vertical circle. The bubbles will be found...
A. near the neck
B. at the bottom
C. at the centre
D. everywhere in the bottle
Answer: A

Question. If the absolute temperature of a gas is doubled, then Vrms will become
A. 2 times
B. √ 2 times
C. 1/2 times
D. 4 times
Answer: B

Question. When the temperature of a black body is lowered to half its original value then the amount of heat radiated will be reduced to...
A. 1/2
B. 1/4
C. 1/
D. 1/16
Answer: D

Question. A shell is fired from a cannon with a velocity V at an angle θ with the horizontal direction. At the highest point in its path it explodes into two pieces of equal mass. One of the pieces retraces its path to the cannon then the speed of the other immediately after the explosion is...
A. 3Vcosθ
B. 2Vcosθ
C. 3/2
D. (√ 3)Vcosθ/2
Answer: A

Question. X-rays have energy of the order of...
A. 10 eV
B. 10⁶ eV
C. infinity
D. zero
Answer: B

Question. In Rutherford model of the atom, the path of an electron will be...
A. a straight line
B. parabolic
C. circular 
D. spiral
Answer: C

Question. A double concave lens of glass, placed in a liquid of refractive index 2, will behave as...
A. diverging lens 
B. concave mirror 
C. converging lens
D. none of the above
Answer: C

Question. Megawattday is the unit of...
A. power
B. force
C. energy
D. density
Answer: C

Question. A particle executes SHM with its frequency f. The frequency with which its kinetic energy oscillates is...
A. f/2
B. f
C. 2f
D. 4f
Answer: C

Question. If the acceleration due to gravity,g, is about 10 m/s2 near the surface of the earth, then at the centre of the earth g would have an approximate value of...
A. zero
B. 5 m/s²
C. 10 m/s² 
D. 20 m/s²
Answer: A

Question. A tuning fork vibrates at a frequency of f Hz. It is viewed through a stroboscopic disc having four equally spaced slots in it. In order for the vibrating tuning fork to appear stationary, the minimum number of revolutions per second at which the disc should be rotated is...
A. f/8
B. f/4
C. f/2
D. f
Answer: B

Question. Which of the following materials has the greatest relative permittivity?
A. Air
B. Glass
C. Mica
D. Water
Answer: D

Question. The distance between two consecutive antinodes is...
A. λ
B. λ/2
C. λ/3
D. λ/4
Answer: B

Question. For an object below the earth's surface, if the distance of the object from earth's centre is 'd', then the acceleration due to gravity is proportional to...
A. d
B. d² 
C. 1/d
D. 1/d²
Answer: A

Question. A type of process that does not need outside energy to reverse is one that occurs at constant...
A. temperature
B. pressure
C. volume
D. speed
Answer: A

Question. Which of the following combinations of length(l) and cross-sectional area(A) will give a certain volume of copper the least resistance?
A. l and A
B. 2l and A/2
C. l/2 and 2A
D. none
Answer: B

Question. Inside a solenoid, the magnetic field...
A. is zero
B. is uniform
C. increases with distance from the axis
D. decreases with distance from the axis
Answer: C

Question. When the voltage are in phase in an a.c. circuit...
A. impedance is zero
B. reactance is zero
C. resistance is zero
D. phase angle is 90°
Answer: B

Question. The distance between two consecutive bright fringes increases as...
A. the wavelength increases
B. the frequency increases
C. the wavelength decreases
D. the separation of two sources increases
Answer: A

Question. Photoelectric effect can be explained on the basis of...
A. the wave theory of light
B. the theory of relativity
C. the theory of black-body radiation
D. none of the above
Answer: D

Question. Acoustics is the branch of physics studying...
A. light
B. heat
C. sound
D. motion of planets
Answer: C

Question. The prefix 'pico' represents...
A. 10^-9
B. 10^-12
C. 10⁹
D. 10¹²
Answer: B

Question. The unit vector in the same direction as(-3i + 4j) is...
A. (-3/5)i + (4/5)j
B. -i + j
C. 3i - 4j
D. (-1/3)i + (1/4)j
Answer: A

Question. An 800-kg car moving at 80 kmph overtakes a 1200-kg car moving at 40 kmph in the same direction. If the two cars stick together,the wreckage has an initial speed of...
A. 8 kmph
B. 40 kmph
C. 56 kmph
D. 60 kmph
Answer: C

Question. For a fixed mass of gas in an isothermal process, the plot of V→(1/p) is...
A. a straight line
B. a parabola
C. a nonparabolic curve
D. a hyperbolic curve
Answer: A

Question. When a vapour condenses into liquid...
A. it absorbs heat
B. it volves heat
C. its temperature rises
D. its temperature falls
Answer: B

Question. For a rectangular glass slab, the entering ray and the emerging ray...
A. are parallel
B. form a right angle
C. form an acute angle
D. form an obtuse angle
Answer: A

Question. The error in measuring the radius of a sphere is 2%. Then the error in the measurement of its volume is...
A. 8%
B. 6%
C. 2%
D. 9%
Answer: B

Question. A magician is throwing rings into air in such a way that when a ring is at its maximum height he throws another ring. If the time difference between each throw is 1 sec then the height attained by the ring is...
A. 49 m
B. 49 cm
C. 9.8 m
D. 4.9 m
Answer: D

Question. If the mass and force are doubled then the acceleration will...
A. double
B. become thrice
C. become four time
D. remain same as before
Answer: D

Question. A string is tied to the neck of a bottle containing soda water and then whirled in a vertical circle. The bubbles will be found...
A. near the neck
B. at the bottom
C. at the centre
D. everywhere in the bottle
Answer: A

Question. If the absolute temperature of a gas is doubled, then Vrms will become
A. 2 times
B. √ 2 times
C. 1/2 times
D. 4 times
Answer: B

Question. When the temperature of a black body is lowered to half its original value then the amount of heat radiated will be reduced to...
A. 1/2
B. 1/4
C. 1/
D. 1/16
Answer: D

Question. A shell is fired from a cannon with a velocity V at an angle θ with the horizontal direction. At the highest point in its path it explodes into two pieces of equal mass. One of the pieces retraces its path to the cannon then the speed of the other immediately after the explosion is...
A. 3Vcosθ
B. 2Vcosθ
C. 3/2
D. (√ 3)Vcosθ/2
Answer: A

Question. X-rays have energy of the order of...
A. 10 eV
B. 10⁶ eV
C. infinity
D. zero
Answer: B

Question. In Rutherford model of the atom, the path of an electron will be...
A. a straight line
B. parabolic
C. circular 
D. spiral
Answer: C

Question. A double concave lens of glass, placed in a liquid of refractive index 2, will behave as...
A. diverging lens 
B. concave mirror 
C. converging lens
D. none of the above
Answer: C

Question. Megawattday is the unit of...
A. power
B. force
C. energy
D. density
Answer: C

Question. A particle executes SHM with its frequency f. The frequency with which its kinetic energy oscillates is...
A. f/2
B. f
C. 2f
D. 4f
Answer: C

Question. If the acceleration due to gravity,g, is about 10 m/s2 near the surface of the earth, then at the centre of the earth g would have an approximate value of...
A. zero
B. 5 m/s²
C. 10 m/s² 
D. 20 m/s²
Answer: A

Question. A tuning fork vibrates at a frequency of f Hz. It is viewed through a stroboscopic disc having four equally spaced slots in it. In order for the vibrating tuning fork to appear stationary, the minimum number of revolutions per second at which the disc should be rotated is...
A. f/8
B. f/4
C. f/2
D. f
Answer: B

Question. Which of the following materials has the greatest relative permittivity?
A. Air
B. Glass
C. Mica
D. Water
Answer: D

Question. The distance between two consecutive antinodes is...
A. λ
B. λ/2
C. λ/3
D. λ/4
Answer: B

Question. For an object below the earth's surface, if the distance of the object from earth's centre is 'd', then the acceleration due to gravity is proportional to...
A. d
B. d² 
C. 1/d
D. 1/d²
Answer: A

Question. A type of process that does not need outside energy to reverse is one that occurs at constant...
A. temperature
B. pressure
C. volume
D. speed
Answer: A

Question. Which of the following combinations of length(l) and cross-sectional area(A) will give a certain volume of copper the least resistance?
A. l and A
B. 2l and A/2
C. l/2 and 2A
D. none
Answer: B

Question. Inside a solenoid, the magnetic field...
A. is zero
B. is uniform
C. increases with distance from the axis
D. decreases with distance from the axis
Answer: C

Question. When the voltage are in phase in an a.c. circuit...
A. impedance is zero
B. reactance is zero
C. resistance is zero
D. phase angle is 90°
Answer: B

Question. The distance between two consecutive bright fringes increases as...
A. the wavelength increases
B. the frequency increases
C. the wavelength decreases
D. the separation of two sources increases
Answer: A

Question. Photoelectric effect can be explained on the basis of...
A. the wave theory of light
B. the theory of relativity
C. the theory of black-body radiation
D. none of the above
Answer: D

Question. Acoustics is the branch of physics studying...
A. light
B. heat
C. sound
D. motion of planets
Answer: C

Question. The prefix 'pico' represents...
A. 10^-9
B. 10^-12
C. 10⁹
D. 10¹²
Answer: B

Question. The unit vector in the same direction as(-3i + 4j) is...
A. (-3/5)i + (4/5)j
B. -i + j
C. 3i - 4j
D. (-1/3)i + (1/4)j
Answer: A

Question. An 800-kg car moving at 80 kmph overtakes a 1200-kg car moving at 40 kmph in the same direction. If the two cars stick together,the wreckage has an initial speed of...
A. 8 kmph
B. 40 kmph
C. 56 kmph
D. 60 kmph
Answer: C

Question. For a fixed mass of gas in an isothermal process, the plot of V→(1/p) is...
A. a straight line
B. a parabola
C. a nonparabolic curve
D. a hyperbolic curve
Answer: A

Question. When a vapour condenses into liquid...
A. it absorbs heat
B. it volves heat
C. its temperature rises
D. its temperature falls
Answer: B

Question. For a rectangular glass slab, the entering ray and the emerging ray...
A. are parallel
B. form a right angle
C. form an acute angle
D. form an obtuse angle
Answer: A

Question. A toy for firing a ball vertically consists of a spring which is compressed 0.10 m by an average force of 5.0 N. If a ball of mass 0.05 kg is placed on the spring and the spring released, the ball will reach a height of ...
A. 1.0 m
B. 1.2 m
C. 1.4 m
D. 1.6 m
Answer: A

Question. A horizontal rope is fixed at one end. The other end is held in the hand and a wave motion is generated by moving the hand up and down repeatedly. A stationary wave is formed and it is observed that a small piece of ribbon tied to the rope is about half way between a node and an adjacent antinode. The movement of the ribbon
A. up and down
B. back and forth
C. a combination of A & B
D. impossible to determine
Answer: A

Question. In an astronomical telescope, the objective lens forms an image that is...
A. real and erect
B. real and inverted
C. virtual and erect
D. virtual and inverted
Answer: B

Question. The specific latent heat of vaporisation of water is 2.3 x 10⁶ J/kg. The percentage of this energy that is necessary to overcome atmospheric pressure is...
A. 0
B. between 0 and 50%
C. 50%
D. between 50 and 100%
Answer: B

Question. The electron-volt is a measure of...
A. charge
B. current
C. potential
D. energy
Answer: D

Question. In which of the following units could Planck's constant be expressed?
A. joule 
B. joule-hertz 
C. joule-second
D. newton-second
Answer: C

Question. The capacitance of a parallel plate capacitor would be decreased by...
A. increasing the separation of the plates
B. increasing the area of overlap of the plates
C. replacing the air between the plates by paper
D. replacing the air between the plates by mica
Answer: A

Question. Two light sources have exactly the same frequency and are always exactly out of step with each other. This is an example of...
A. phase reversal
B. Huygen's principle 
C. coherence
D. destructive interference
Answer: C

Question. Two bodies of mass m1 and m2 are moving with equal kinetic energy.The ratio of their linear momentum P₁ : P₂ is...
A. m₁ : m₂
B. m₂ : m₁ 
C. m₁₂ : m_2² 
D. √m₁ : √m₂
Answer: D

Question. The force required to make the length of a wire three times its original length is ____ when the area of cross-section is unity and Y is the Young's modulus.
A. 2Y
B. 3Y
C. Y 
D. Y/2
Answer: A

Question. The first law of thermodynamics is a special case of...
A. law of conservation of momentum
B. law of conservation of energy
C. Boyle's law
D. Charles' law
Answer: B

Question. If the velocity of sound in air at 0°C is 300 m/s, at what temperature will the velocity be 400 m/s?
A. 330°C
B. 485°C
C. 674°C
D. 1000°C
Answer: B

Question. A ray of light incident on a 60° angled prism of refractive index √ 2, suffers minimum deviation. The angle of incidence is...
A. 75°
B. 0°
C. 45° 
D. 60°
Answer: C

Question. Two equal negative charges(-q) are fixed at two points (0,a) and (0,-a) on the Y-axis. A positive charge q is released from rest at the point (2a,0) on the X-axis. The charge q will...
A. execute SHM about the origin
B. move to the origin and remain at rest
C. move to infinity
D. execute oscillatory motion but not SHM
Answer: A

Question. Ball-point pen functions on the principle of
A. viscosity
B. Boyle's law
C. gravitational force
D. surface tension
Answer: D

Question. A soap bubble has a radius of 3 cm. The surface tension of soap solution is 1.5 x 10^-2 N/m. The excess of pressure (in N/m²) is equal to...
A. 1
B. 2
C. 0.5 x 10^-2
D. 1.0 x 10^-2
Answer: B

Question. In case of a prism, the angle of deviation is greater for...
A. violet
B. red
C. blue
D. green
Answer: A

Question. A piece of copper and another of germanium are cooled from room temperature to 80K. The resistance of...
A. each of them increases
B. each of them decreases
C. copper increases and germanium decreases
D. copper decreases and germanium increases
Answer: D

Question. Which of the following is always attractive?
A. Strong force
B. Electrostatic force
C. Magnetic force
D. None of the three
Answer: A

Question. A non-conservative force does not give rise to...
A. thermal energy
B. kinetic energy
C. light energy
D. potential energy
Answer: D

Question. If E_A is the energy required for the equilibrium separation of two hydrogen atoms in a molecule of hydrogen and E_M is the energy required for the equilibrium separation of two molecules of hydrogen, then
A. E_A = E_M
B. E_A = E_M/(√ 2)
C. E_A > E_M
D. E_A < Em
Answer: C

Question. When pressure of 2.0 MPa is applied to a sample of kerosene, it contracts by 15%. The bulk modulus of kerosene is...
A. 1.7 MPa
B. 1.997 MPa
C. 2.003 MPa
D. 1.3 GPa
Answer: D

Question. A wetting agent...
A. reduces angle of contact
B. increases angle of contact
C. increases surface tension
D. increases surface area
Answer: A

Question. When a slab of insulating material is introduced in a capacitor, its capacitance
A. becomes zero
B. decreases considerably
C. increases considerably
D. does not change
Answer: C

Question. For a constant-length pendulum, the periodic time depends on
A. amplitude
B. length
C. mass of pendulum
D. 'g'
Answer: D

Question. The amplitude of a sound wave determines its...
A. pitch
B. loudness
C. overtones
D. resonance
Answer: B

Question. The value of 'g' at pole is...
A. greater than that at the equator
B. smaller than that at the equator
C. equal to that at the equator
D. zero
Answer: A

Question. Which of the following engines is the most efficient?
A. gasoline
B. diesel
C. gas turbine
D. Carnot
Answer: D

Question. A 50-V battery is connected across a 10-ohm resistor and a current of 4.5 A flows. The internal resistance of the battery is...
A. 0
B. 0.5 ohm
C. 1.1 ohm
D. 5 ohm
Answer: C

Question. In an LCR series circuit Q-factor is given by...
A. 1/√LC
B. √(L/C)
C. (1/R).√(L/C)
D. R/(√LC)
Answer: C

Question. For an object performing SHM the magnitude of maximum velocity is given by...
A. ω √(A² - y²)
B. ω √(y² - A²)
C. ωA
D. ω²A
Answer: C

Question. The reciprocal of wavelength is called...
A. frequency
B. wave velocity
C. amplitude
D. wave number
Answer: D

Question. ______ is for rotational motion as mass is for linear motion.
A. mass 
B. torque
C. moment of inertia
D. inertia
Answer: C

Question. If m is the mass of a planet, r is radius of its orbit, ω is the angular velocity and v is its linear velocity, then the force acting on planet is...
A. mrv²
B. mr²V²
C. mrω²
D. mr²ω²
Answer: C

Question. In a fuel cell the conversion of chemical energy into electrical energy takes place...
A. at both electrodes
B. at the anode only
C. at the cathode only
D. in the electrolyte
Answer: A

Question. Which of the following is not the unit of magnetic flux?
A. weber
B. tesla-m²  
C. m²kgs^-1
D. henry
Answer: D

Question. Impulse is equal to...
A. momentum
B. change in momentum
C. change in momentum per unit time
D. change in momentum per unit mass
Answer: B

Question. 1 kWh is equal to...
A. 746 W
B. 3.6 x 106 J
C. 3.6 hp
D. 746 kW
Answer: B

Question. The atomic mass of copper is 64 and its density is 9.0 g/cm³. The volume of one mole of atoms of copper is _____ g/cm3.
A. 6.023 x 10²³
B. (6.023 x 9 x 10²³)/64
C. (6.023 x 64 x 10²³)/9
D. 64/9
Answer: B

Question. Young's modulus for aluminium is 7 x 10¹⁰ Pa. The force needed to stretch, an aluminium wire with 2 mm diameter and 800 mm length, by 1 mm is...
A. 2.75 N
B. 275 N
C. 1.10 N
D. 275 kN
Answer: B

Question. The MKS unit of coefficient of viscosity is...
A. poise
B. centipoise
C. Pa second^-1
D. Pa second
Answer: D

Question. Electric charge is quantized. This means that the electric charge...
A. is not continuous
B. is continuous
C. is constant
D. has mass
Answer: A

Question. A 2 kg ball moves with a speed of 8 m/s and collides with a 4 kg ball moving in the same direction with a speed of 2 m/s. After the collision, the heavier ball has a speed of 5 m/s. The collision results in a decrease in the total kinetic energy of translation of two balls of...
A. 0 J
B. 6 J
C. 12 J
D. 18 j
Answer: D

Question. The result of combining two mutually perpendicular vibrations was first extensively studied by...
A. Huygens
B. Lissajon
C. Sabine
D. Newton
Answer: B

Question. On a sunny day you may see very bright lines formed on the bottom of a swimming pool. The prime cause of these is...
A. absorption
B. diffraction 
C. interference 
D. refraction
Answer: D

Question. A piece of glass which has been heated to a high temperature is left to cool. If the glass cracks, it will most likely be because of...
A. low thermal conductivity of glass 
B. high thermal conductivity of glass
C. low specific heat capacity of glass 
D. high specific heat capacity of glass
Answer: A

Question. The charge to mass ratio of an electron is about 1.8 x 10¹¹ C kg^-1. In a certain television tube, where the accelerating voltage is 1600V, the electrons have a speed just before striking the screen of approximately...
A. 16000 kms^-1
B. 20000 kms^-1
C. 24000 kms^-1
D. 28000 kms^-1
Answer: C

Question. A mass spectrometer may be used to distinguish between...
A. different elements
B. different isotopes
C. identical isotopes bearing different charge
D. all of the above
Answer: D

Question. If a train is to move with velocity of light, its length would be
A. infinite
B. unchanged
C. zero
D. half the original
Answer: C

Question. A radio-station broadcasts at 30 m band. The frequency of electromagnetic waves transmitted from this station could be...
A. 10 MHz
B. 10 kHz
C. 3 x 10¹⁰ Hz
D. 11 x 10¹¹ Hz
Answer: A

Question. The energy generation in stars is due to...
A. fusion of heavy nuclei
B. fusion of light nuclei
C. chemical reaction
D. fission of heavy nuclei
Answer: B

Question. Two resistances are joined in parallel whose resultant is 6/5 ohm. One of the resistance wires is broken and the effective resistance becomes 2 ohm. The resistance in ohm of the wire that got broken is...
A. 2
B. 3
C. 3/5
D. 6/5
Answer: B

Question. When the distance between a source and a cliff is 'd', the time taken to hear the first echo of sound with velocity 'V' is...
A. V.d
B. 2V/d
C. 2d/V
D. d/V
Answer: C

Question. Which of the following pairs of physical quantities have the same unit?
A. Force and power
B. Stress and strain
C. Young's modulus and pressure
D. Coefficient of viscosity and surface tension
Answer: C

Question. The area enclosed by the displacement-time graph of a body thrown in air gives...
A. average speed
B. average velocity
C. acceleration
D. no significant physical quantity
Answer: D

Question. A particle is moving eastwards with a velocity of 5 m/s. In 10 seconds the velocity changes to 5 m/s northwards. The average acceleration in this time is...
A. zero
B. (1/√ 2) m/s² towards northwest
C. (1/√ 2) m/s² towards northeast
D. (1/2) m/s² towards northwest
Answer: B

Question. Swimming becomes possible because of _____ law of motion.
A. First
B. Second
C. Third
D. none of the three
Answer: C

Question. A thin film of liquid is enclosed between two glass plates. It is difficult to separate the plates on account of...
A. Viscosity
B. Surface tension
C. Friction
D. Atmospheric pressure
Answer: B

Question. The highest temperature that can be recorded by a mercury thermometer is...
A. 100°C
B. 157°C
C. 257°C
D. 357°C
Answer: C

Question. A tuning fork originally in unison with another fork of frequency 260 Hz, produces 4 beats per second, when a little wax is attached to it. What is the frequency now?
A. 260 Hz
B. 264 Hz
C. 256 Hz
D. 262 H
Answer: C