Physical World, Units & Measurements Biology | Chemistry | Physics | NTA Please enter your email: The dimensional formula of the constant a in Vander Waal’s gas equation(P+a⁄V2)(V-b)=RT is (a) [ML4T–1] (b) [ML2T–2 ] (c) [ML5T–3 ] (d) [ML5T–2 ] 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 Which of the following is a dimensional constant? (a) Refractive index (b) Poissons ratio (c) Strain (d) Gravitational constant 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 A force F is applied onto a square plate of side L. If the percentage error in determining L is 2% and that in F is 4%, the permissible percentage error in determining the pressure is (a) 2% (b) 4% (c) 6% (d) 8% Parsec is the unit of (a) time (b) distance (c) frequency (d) angular acceleration 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% The siemen is the SI unit of (a) resistivity (b) resistance (c) conductivity (d) conductance 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] Weber is the unit of (a) magnetic susceptibility (b) intensity of magnetisation (c) magnetic flux (d) magnetic permeability If L = 2.331 cm, B = 2.1 cm, then L + B = (a) 4.431 cm (b) 4.43 cm (c) 4.4 cm (d) 4 cm If E, m, J and G represent energy, mass, angular momentum and gravitational constant respectively, then the dimensional formula of EJ2/m5G2 is same as that of the (a) angle (b) length (c) mass (d) time The dimensions of mobility are (a) M–2T2A (b) M–1T2A (c) M–2T3A (d) M–1T3A The dimensional formula of magnetic flux is (a) [ML0T–2A–1] (b) [ML2T–2A–1] (c) [ML2T–1A3] (d) [M0L–2T–2A–2] 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 Unit of magnetic moment is (a) ampere–metre2 (b) ampere–metre (c) weber–metre (d) weber/metre The dimensions of Wien’s constant are (a) [ML0TK] (b) [M0LT0K] (c) [M0L0TK] (d) [MLTK] The dimensions of 1/εo e2/hc are (a) M-1 L-3 T4 A2 (b) ML3 T-4 A-2 (c) M0 L0 T0 A0 (d) M-1 L-3 T2 A 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 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 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% An object is moving through the liquid. The viscous damping force acting on it is proportional to the velocity. Then dimensions of constant of proportionality are (a) [ML-1T-1] (b) [MLT-1] (c) [M0LT-1] (d) [ML0T-1] Which two of the following five physical parameters have the same dimensions? (A) Energy density (B) Refractive index (C) Dielectric constant (D) Young’s modulus (E) Magnetic field (a) (B) and (D) (b) (C) and (E) (c) (A) and (D) (d) (A) and (E) Velocity of light is equal to (a) √(1 /ε0μ0) (b) √(ε0 / μ0) (c) ε0 / μ0 (d) ε0μ 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 dimensional formula for torque is (a) ML2T–2 (b) ML–1T–1 (c) L2T–1 (d) M2T–2K–1 Dimensions of electrical resistance are (a) [ML2T–3A–1] (b) [ML2T–3A–2] (c) [ML3T–3A–2] (d) [ML–1L3T3A2] Dimensions of coefficient of viscosity is (a) [MT2] (b) [ML–3T–4] (c) [ML–1T–2] (d) [ML–1T–1] 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 Which is different from others by units? (a) Phase difference (b) Mechanical equivalent (c) Loudness of sound (d) Poisson’s ratio 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 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 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 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 speed of light (c), gravitational constant (G) and planck’s constant (h) are taken as fundamental units in a system. The dimensions of time in this new system should be (a) G1/2 h1/2 c–5/2 (b) G–1/ 2 h1/ 2 c1/ 2 (c) G1/ 2 h1/ 2 c–3/ 2 (d) G1/ 2 h1/ 2 c1/ 2 The dimensions of Reynold’s constant are (a) [M0L0T0] (b) [ML–1T–1] (c) [ML–1T–2] (d) [ML–2T–2] What is the dimensional formula of gravitational constant? (a) [ML2T–2 ] (b) [ML–1T–1] (c) [M–1L3T–2 ] (d) none of these The refractive index of water measured by the relation m = real depth⁄ apparent depth, is found to have values of 1.34, 1.38, 1.32 and 1.36; the mean value of refractive index with percentage error is (a) 1.35 ± 1.48 % (b) 1.35 ± 0 % (c) 1.36 ± 6 % (d) 1.36 ± 0 % The unit of impulse is the same as that of (a) energy (b) power (c) momentum (d) velocity The dimensions of Planck’s constant are (a) [ML–3T–1] (b) [ML–2T–1] (c) [M0L–1T–3] (d) [ML2T–1] Young’s modulus of a material has the same unit as that of (a) pressure (b) strain (c) compressibility (d) force The dimensional formula for magnetic flux is (a) [ML2T–2A–1] (b) [ML3T–2A–2] (c) [M0L–2T2A–2] (d) [ML2T–1A2] 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 physical quantity which has the dimensional formula [M1T-3] is (a) surface tension (b) solar constant (c) density (d) compressibility 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 Loading … Question 1 of 45
