Physical World, Units & Measurements Biology | Chemistry | Physics | NTA Please enter your email: 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 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 ] Young’s modulus of a material has the same unit as that of (a) pressure (b) strain (c) compressibility (d) force The dimensions of Reynold’s constant are (a) [M0L0T0] (b) [ML–1T–1] (c) [ML–1T–2] (d) [ML–2T–2] 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 the capacitance of a nanocapacitor is measured in terms of a unit ‘u‘ made by combining the electric charge ‘e‘, Bohr radius ‘ao‘, Planck’s constant ‘h‘ and speed of light ‘c‘ then (a) u=e2h/ao (b) u=hc/e2ao (c) u=e2c/hao (d) u=e2ao/hc Dimensions of coefficient of viscosity is (a) [MT2] (b) [ML–3T–4] (c) [ML–1T–2] (d) [ML–1T–1] The dimensions of mobility are (a) M–2T2A (b) M–1T2A (c) M–2T3A (d) M–1T3A 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] 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 dimensional formula of farad is (a) [M–1L–2TQ] (b) [M–1L–2T2Q2] (c) [M–1L–2TQ2 ] (d) [M–1L–2T2Q] 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 siemen is the SI unit of (a) resistivity (b) resistance (c) conductivity (d) conductance Weber is the unit of (a) magnetic susceptibility (b) intensity of magnetisation (c) magnetic flux (d) magnetic permeability The dimensional formula for magnetic flux is (a) [ML2T–2A–1] (b) [ML3T–2A–2] (c) [M0L–2T2A–2] (d) [ML2T–1A2] Of the following quantities, which one has dimensions different from the remaining three? (a) Energy per unit volume (b) Force per unit area (c) Product of voltage and charge per unit volume (d) Angular momentum The dimensions of Planck’s constant are (a) [ML–3T–1] (b) [ML–2T–1] (c) [M0L–1T–3] (d) [ML2T–1] Which of the following pairs does not have similar dimensions? (a) tension and surface tension (b) stress and pressure (c) Planck’s constant and angular momentum (d) angle and strain 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 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 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% 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 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 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 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 energy are (a) [ML3T–3] (b) [ML–1T–1] (c) [ML2T–2] (d) [MT–2] What is the dimensions of impedance? (a) ML2T–3I–2 (b) M–1L–2T3I2 (c) ML3T–3I–2 (d) M–1L–3T3I2 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] 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) 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 dimensions of 1⁄2 ε0E2 ( ε0 : permittivity of free space, E electric field) are (a) [MLT–1] (b) [ML2T–2] (c) [ML–1T–2] (d) [ML2T–1] The dimensional formula for torque is (a) ML2T–2 (b) ML–1T–1 (c) L2T–1 (d) M2T–2K–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 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 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 unit of impulse is the same as that of (a) energy (b) power (c) momentum (d) velocity 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 Which is different from others by units? (a) Phase difference (b) Mechanical equivalent (c) Loudness of sound (d) Poisson’s ratio Velocity of light is equal to (a) √(1 /ε0μ0) (b) √(ε0 / μ0) (c) ε0 / μ0 (d) ε0μ The dimensions of Wien’s constant are (a) [ML0TK] (b) [M0LT0K] (c) [M0L0TK] (d) [MLTK] The velocity of water waves (v) may depend on their wavelength l, the density of water r and the acceleration due to gravity, g. The method of dimensions gives the relation between these quantities is (a) v (b) v2 α gλ (c) v2 α gλ2 (d) v2 α g–1λ2 What is the dimensional formula of gravitational constant? (a) [ML2T–2 ] (b) [ML–1T–1] (c) [M–1L3T–2 ] (d) none of these The respective number of significant figures for the numbers 23.023, 0.0003 and 2.1 × 10-3 are (a) 5, 1, 2 (b) 5, 1, 5 (c) 5, 5, 2 (d) 4, 4, 2 The physical quantity which has the dimensional formula [M1T-3] is (a) surface tension (b) solar constant (c) density (d) compressibility 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 Loading … Question 1 of 45