Free NEET Physics multiple-choice questions on Units & SI System. Attempt each question and reveal the answer with a full explanation.
Which of the following is the unit of 'Luminous Flux'? Lumen Candela Lux Watt The unit of 'Calorific Value' in SI units is: J kg -1 J kg W kg -1 kg J -1 The unit of 'Absorbed Dose' of ionizing radiation in the SI system is: Gray Sievert Becquerel Curie The unit of permittivity of free space 0 is: C 2 N -1 m -2 N m 2 C -2 C 2 N m -2 C 2 N -1 m 2 The unit of 'Luminous Intensity' is 'Candela'. Its dimensions are: [J] [M 0 L 0 T 0] [Cd] [I] The unit of 'Parsec' is used to measure: Distance Time Frequency Angular momentum The damping force on an oscillator is directly proportional to the velocity. The units of the constant of proportionality are: kg s -1 kg m s -1 kg m s -2 kg s Which of the following is a unit of distance? Light year Microsecond Leap year Lunar month The unit of 'Wave Number' is: m -1 m s -1 dimensionless The unit of 'Reactance' is: Ohm Farad Henry Siemens Which of the following is not a base SI unit? Coulomb Candela Mole Ampere What is the unit of 'Luminous Flux' in the SI system? Lumen Candela Lux Watt The unit of 'Magnetic Flux Density' is: Tesla Weber Henry Oersted The 'Quality Factor' (Q-factor) of an LCR circuit is: Dimensionless Having dimensions of Time Having dimensions of Frequency Having dimensions of Resistance Poisson's ratio is: Dimensionless Dimensions of Stress Dimensions of Strain Dimensions of Young's Modulus The unit of 'Luminous Flux' is: Lumen Candela Lux Watt What is the unit of 'Magnetic Dipole Moment' in SI units? A m 2 A/m 2 A m T m 2 The unit of 'Power of a Lens' is Dioptre, which is equivalent to: m -1 m cm -1 cm The unit of 'Intensity of Sound' is: W/m 2 J/m 2 W/m N/m 2 Which of the following is a base SI unit? Candela Joule Newton Volt If 10 divisions of a circular scale of a screw gauge are equal to 1 mm on the main scale, then the pitch of the screw gauge is: 1 mm 0.1 mm 10 mm 0.01 mm What is the unit of 'Magnetic Intensity' ( H ) in the SI system? A/m A m A/m 2 Tesla The SI unit of 'Conductivity' is: S m -1 S m m m -1 A spherometer is used to measure the: Radius of curvature of a lens Diameter of a thin wire Thickness of a paper Depth of a small hole Which of the following units is used for the measurement of the 'Activity' of a radioactive source? Becquerel Siemens Henry Weber The ratio of the dimension of Planck's constant and that of the moment of inertia is the dimension of : Velocity Angular momentum Time Frequency The velocity v of a particle at time t is given by v = at + b t+c , where a, b and c are constants. The dimensions of a, b and c are respectively:- LT -2 , L and T L 2, T and LT 2 LT 2, LT and L L, LT and T 2 Dimensions of resistance in an electrical circuit, in terms of dimension of mass M, of length L, of time T and of current I, would be ML 2T -2 ML 2T -1 I -1 ML 2T -3 I -2 ML 2T -3 I -1 If the dimensions of a physical quantity are given by [M aL bT c] , then the physical quantity will be : Force if a = 0, b = -1, c = -2 Pressure if a = 1, b = -1, c = -2 Velocity if a = 1, b = 0, c = -1 Acceleration if a = 1, b = 1, c = -2 If force (F), velocity (V) and time (T) are taken as fundamental units, then the dimensions of mass are:- [F V T -1 ] [F V T -2 ] [F V -1 T -1 ] [F V -1 T] The energy required to break one bond in DNA is 10 -20 J . This value in eV is nearly: 0.6 0.06 0.006 6 Dimensions of stress are : [ML 2T -2 ] [ML 0T -2 ] [ML -1 T -2 ] [MLT -2 ] If E and G respectively denote energy and gravitational constant, then E G has the dimensions of [M] [L -1 ] [T -1 ] [M] [L 0 ] [T 0 ] [M 2 ] [L -2 ] [T -1 ] [M 2 ] [L -1 ] [T 0 ] The unit of 'Wave Number' is: m -1 m s -1 dimensionless Which one of the following methods can be used to obtain highly pure metal which is liquid at room temperature? Chromatography Distillation Zone refining Electrolysis Plane angle and solid angle have Dimensions but no units No units and no dimensions Both units and dimensions Units but no dimensions The quantities which have the same dimensions as those of solid angle are: strain and angle stress and angle strain and arc angular speed and stress A force defined by F = t 2 + t acts on a particle at a given time t . The factor which is dimensionless, if and are constants, is: t t t t The speed of light in vacuum is taken as unity. If light takes 6 min 40 s to reach the Earth from the Sun, the distance between the Sun and the Earth in new unit is: 3 10 8 500 3 10 10 400 The unit of thermal conductivity is: W m -1 K -1 W m K -1 J m K -1 J m -1 K -1 The unit of 'Stefan's constant' is: W m -2 K -4 J m -2 K -4 W m -1 K -4 W m -2 K -2 The value of 'Planck's constant' in SI units is 6.63 10 -34 J s . Its dimensions are [ML 2T -1 ] . What is its value in CGS units? 6.63 10 -27 erg s 6.63 10 -34 erg s 6.63 10 -41 erg s 6.63 10 -31 erg s The SI unit of 'Electric Quadrupole Moment' is: C m 2 C m C/m 2 V m The unit of 'Magnetic Permeability' in SI is: T m / A T A / m Wb m / A T/m The unit of 'Luminous Intensity' in SI system is: candela lumen lux watt The unit of 'Surface Tension' in CGS system is 70 dyne/cm . In SI units, its value is: 0.07 N/m 7 N/m 700 N/m 0.7 N/m Which of the following is NOT a unit of distance? Barn Astronomical Unit Light year Parsec The unit of 'Viscosity' in the SI system is 'Poiseuille' (or Pa s ). The relation between 1 Poiseuille and the CGS unit 'Poise' is: 1 Poiseuille = 10 Poise 1 Poiseuille = 1 Poise 10 Poiseuille = 1 Poise 1 Poiseuille = 100 Poise Which of the following represents the correct unit for 'Magnetic Induction'? kg s -2 A -1 kg m s -2 A -1 kg m 2 s -2 A -1 kg m -1 s -1 The 'Parsec' is a unit of length used in astronomy. 1 Parsec is approximately equal to: 3.08 10 16 m 9.46 10 15 m 1.49 10 11 m 3 10 8 m The unit of 'Inductance' expressed in SI base units is: kg m 2 s -2 A -2 kg m 2 s -3 A -2 kg m s -2 A -2 kg m 2 s -2 A -1 The fraction of total volume occupied by the atoms present in a simple cube is 3 2 4 2 4 6 Lithium metal crystallizes in a body centred cubic crystal. If the length of the side of the unit cell of lithium is 351 pm, the atomic radius of lithium will be : 300.5 pm 240.8 pm 151.8 pm 75.5 pm An element has a body centered cubic (bcc) structure with a cell edge of 288 pm. The atomic radius is 2 4 288 pm 4 3 288 pm 4 2 288 pm 3 4 288 pm If force [F], acceleration [A] and time [T] are chosen as the fundamental physical quantities. Find the dimensions of energy. [F][A][T 2] [F][A][T -1 ] [F][A -1 ][T] [F][A][T] Which of the following is not a unit of length? Shake Angstrom Fermi Parsec The correct option for the number of body centred unit cells in all 14 types of Bravais lattice unit cells is : 5 2 3 7 The dimensions [ MLT -2 A -2 ] belong to the Self inductance Magnetic permeability Electric permittivity Magnetic flux Match List-I with List-II array llll ; & List-I & ; & List-II (a) & Gravitational constant (G) & (i) & [L 2T -2 ] (b) & Gravitational potential energy & (ii) & [M -1 L 3T -2 ] (c) & Gravitational potential & (iii) & [LT -2 ] (d) & Gravitational intensity & (iv) & [ML 2T -2 ] array Choose the correct answer from the options given below (a) - (ii), (b) - (iv), (c) - (i), (d) - (iii) (a) - (ii), (b) - (iv), (c) - (iii), (d) - (i) (a) - (iv), (b) - (ii), (c) - (i), (d) - (iii) (a) - (ii), (b) - (i), (c) - (iv), (d) - (iii) A balloon is made of a material of surface tension S and its inflation outlet (from where gas is filled in it) has small area A . It is filled with a gas of density and takes a spherical shape of radius R . When the gas is allowed to flow freely out of it, its radius r changes from R to 0 (zero) in time T . If the speed v(r) of gas coming out of the balloon depends on r as r a and T S A R then a= 1 2 , = 1 2 , =- 1 2 , = 1 2 , = 7 2 a= 1 2 , = 1 2 , =-1, =+1, = 3 2 a=- 1 2 , =- 1 2 , =-1, =- 1 2 , = 5 2 a=- 1 2 , =- 1 2 , =-1, = 1 2 , = 7 2 Iron exhibits bcc structure at room temperature. Above 900 C , it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900 C (assuming molar mass and atomic radii of iron remains constant with temperature) is 3 3 4 2 4 3 3 2 3 2 1 2 Copper crystallises in fcc unit cell with cell edge length of 3.608 10 -8 cm . The density of copper is 8.92 g cm -3 . Calculate the atomic mass of copper. 31.55 u 60 u 65 u 63.1 u The 'Barn' is a unit used to measure which of the following physical quantities in nuclear physics? Cross-sectional area Volume Mass density Magnetic flux The SI unit of 'Electric Dipole Moment' expressed in base units is: A s m A m kg m s A A 2 s m Which of the following is not the unit of time? Parallactic second Microsecond Leap year Lunar month