Physical World, Units & Measurements Biology | Chemistry | Physics | NTA Please enter your email: A quantity X is given by εoL ΔV⁄Δt where εo is the permittivity of the free space, L is a length, ΔV is a potential difference and Δt is a time interval. The dimensional formula for X is the same as that of (a) resistance (b) charge (c) voltage (d) current Using mass (M), length (L), time (T) and current (A) as fundamental quantities, the dimensional formula of permittivity is (a) [ML–2T2A] (b) [M–1L–3T4A2] (c) [MLT–2A] (d) [ML2T–1A2] The magnetic moment has dimensions of (a) [LA] (b) [L2A] (c) [LT–1A] (d) [L2T–1A] Two quantities A and B have different dimensions which mathematical operation given below is physically meaningful? (a) A/B (b) A + B (c) A – B (d) A = B If the error in the measurement of the volume of sphere is 6%, then the error in the measurement of its surface area will be (a) 2% (b) 3% (c) 4% (d) 7.5% If e is the charge, V the potential difference, T the temperature, then the units of eV /T are the same as that of (a) Planck’s constant (b) Stefan’s constant (c) Boltzmann’s constant (d) gravitational constant The density of a cube is measured by measuring its mass and length of its sides. If the maximum error in the measurement of mass and length are 4% and 3% respectively, the maximum error in the measurement of density will be (a) 7% (b) 9% (c) 12% (d) 13% The time period of a body under S.H.M. is represented by: T = Pa Db Sc where P is pressure, D is density and S is surface tension, then values of a, b and c are (a) –3⁄2, 1⁄2, 1 (b) –1, –2, 3 (c) 1⁄2, –3⁄2, –1⁄2 (d) 1, 2, 1⁄3 The dimensions of Wien’s constant are (a) [ML0TK] (b) [M0LT0K] (c) [M0L0TK] (d) [MLTK] The unit of impulse is the same as that of (a) energy (b) power (c) momentum (d) velocity What is the fractional error in g calculated from T = 2π √l/ g? Given fraction errors in T and l are ± x and ± y respectively? (a) x + y (b) x – y (c) 2x + y (d) 2x – y If Q denote the charge on the plate of a capacitor of capacitance C then the dimensional formula for Q2/C is (a) [L2M2T] (b) [LMT2] (c) [L2MT–2] (d) [L2M2T2] The physical quantities not having same dimensions are (a) torque and work (b) momentum and Planck’s constant (c) stress and Young’s modulus (d) speed The Richardson equation is given by I=AT2e—B/kT. The dimensional formula for AB2 is same as that for (a) I T2 (b) kT (c) I k2 (d) I k2/T The dimensions of energy are (a) [ML3T–3] (b) [ML–1T–1] (c) [ML2T–2] (d) [MT–2] The dimensional formula for magnetic flux is (a) [ML2T–2A–1] (b) [ML3T–2A–2] (c) [M0L–2T2A–2] (d) [ML2T–1A2] Which of the following pair of quantities do not have the same dimensions (a) Potential gradient, electric field (b) Torque, kinetic energy (c) Light year, time period (d) Impedance, reactance Using mass (M), length (L), time (T) and current (A) as fundamental quantities, the dimensions of permeability are (a) [M–1LT–2A] (b) [ML–2T–2A–1] (c) [MLT–2A–2] (d) [MLT–1A–1] The physical quantity which has the dimensional formula [M1T-3] is (a) surface tension (b) solar constant (c) density (d) compressibility The pressure on a square plate is measured by measuring the force on the plate and length of the sides of the plate by using the formula P = F/l2. If the maximum errors in the measurement of force and length are 4% and 2% respectively, then the maximum error in the measurement of pressure is (a) 1% (b) 2% (c) 8% (d) 10% Dimensions of electrical resistance are (a) [ML2T–3A–1] (b) [ML2T–3A–2] (c) [ML3T–3A–2] (d) [ML–1L3T3A2] Multiply 107.88 by 0.610 and express the result with correct number of significant figures. (a) 65.8068 (b) 65.807 (c) 65.81 (d) 65.8 The siemen is the SI unit of (a) resistivity (b) resistance (c) conductivity (d) conductance If velocity (V), force (F) and energy (E) are taken as fundamental units, then dimensional formula for mass will be (a) V-2F0E (b) V0FE2 (c) VF–2E0 (d) V-2F0E The mass of the liquid flowing per second per unit area of cross-section of the tube is proportional to (pressure difference across the ends)n and (average velocity of the liquid)n. Which of the following relations between m and n is correct? (a) m = n (b) m = – n (c) m2 = n (d) m = – n2 Weber is the unit of (a) magnetic susceptibility (b) intensity of magnetisation (c) magnetic flux (d) magnetic permeability Velocity of light is equal to (a) √(1 /ε0μ0) (b) √(ε0 / μ0) (c) ε0 / μ0 (d) ε0μ Which of the following physical quantities do not have same dimensions? (a) pressure and stress (b) tension and surface tension (c) strain and angle (d) energy and work The dimensional formula for torque is (a) ML2T–2 (b) ML–1T–1 (c) L2T–1 (d) M2T–2K–1 Young’s modulus of a material has the same unit as that of (a) pressure (b) strain (c) compressibility (d) force The dimensions of Planck’s constant are (a) [ML–3T–1] (b) [ML–2T–1] (c) [M0L–1T–3] (d) [ML2T–1] The dimensional formula of magnetic flux is (a) [ML0T–2A–1] (b) [ML2T–2A–1] (c) [ML2T–1A3] (d) [M0L–2T–2A–2] In a vernier callipers, ten smallest divisions of the vernier scale are equal to nine smallest division on the main scale. If the smallest division on the main scale is half millimeter, then the vernier constant is (a) 0.5 mm (b) 0.1 mm (c) 0.05 mm (d) 0.005 mm Unit of magnetic moment is (a) ampere–metre2 (b) ampere–metre (c) weber–metre (d) weber/metre The dimensions of mobility are (a) M–2T2A (b) M–1T2A (c) M–2T3A (d) M–1T3A Parsec is the unit of (a) time (b) distance (c) frequency (d) angular acceleration The least count of a stop watch is 0.2 second. The time of 20 oscillations of a pendulum is measured to be 25 second. The percentage error in the measurement of time will be (a) 8% (b) 1.8% (c) 0.8% (d) 0.1% An experiment is performed to obtain the value of acceleration due to gravity g by using a simple pendulum of length L. In this experiment time for 100 oscillations is measured by using a watch of 1 second least count and the value is 90.0 seconds. The length L is measured by using a meter scale of least count 1 mm and the value is 20.0 cm. The error in the determination of g would be: (a) 1.7% (b) 2.7% (c) 4.4% (d) 2.27% The dimensions of Reynold’s constant are (a) [M0L0T0] (b) [ML–1T–1] (c) [ML–1T–2] (d) [ML–2T–2] What is the dimensions of impedance? (a) ML2T–3I–2 (b) M–1L–2T3I2 (c) ML3T–3I–2 (d) M–1L–3T3I2 Which of the following is a dimensional constant? (a) Refractive index (b) Poissons ratio (c) Strain (d) Gravitational constant The density of material in CGS system of units is 4g/cm3. In a system of units in which unit of length is 10 cm and unit of mass is 100 g, the value of density of material will be (a) 0.4 unit (b) 40 unit (c) 400 unit (d) 0.04 unit The dimensional formula of farad is (a) [M–1L–2TQ] (b) [M–1L–2T2Q2] (c) [M–1L–2TQ2 ] (d) [M–1L–2T2Q] What is the dimensional formula of gravitational constant? (a) [ML2T–2 ] (b) [ML–1T–1] (c) [M–1L3T–2 ] (d) none of these Which is different from others by units? (a) Phase difference (b) Mechanical equivalent (c) Loudness of sound (d) Poisson’s ratio Loading … Question 1 of 45
