Physics and Measurement
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See all →- A physical quantity P is related to four observations a, b, c and d as follows:P = a^3b^2 / c√(d)The percentage errors of measurement in a, b, c and d are 1%, 3%, 2%, and 4% respectively. The percentage error in the quantity P is Answer: 3. 13% Key idea: for P=a³b²/csqrt d , the maximum percentage error is the sum of (power × percentage error) of each quantity. Δ P/P×... 1
- A force defined by F=α t^2+β t acts on a particle at a given time t. The factor which is dimensionless, if α and β are constants, is: Answer: 3. α t/β Key idea: Every term in a physical formula has the same dimensions as F , so α t² and β t have the dimensions of force. Equ... 1
- The quantities which have the same dimensions as those of solid angle are : Answer: 2. strain and angle Key idea: Solid angle (like plane angle) is a ratio of two lengths/areas, so it is dimensionless. Strain (change... 1
- The errors in the measurement which arise due to unpredictable fluctuations in temperature and voltage supply are : Answer: 1. Random errors Errors that arise from unpredictable, irregular fluctuations in conditions such as temperature or voltage supply ar... 1
- A metal wire has mass (0.4±0.002) g, radius (0.3±0.001) mm and length (5±0.02) cm. The maximum possible percentage error in the measurement of density will nearly be: Answer: 4. 1.6% Density ρ=m/π r² l . The maximum fractional errors add, with the radius error counted twice because of r² . Δρ/ρ=Δ m/m+2Δ r/... 1
- Match List - I with List - II :List - I: (a) Gravitational constant (G) (b) Gravitational potential energy (c) Gravitational potential (d) Gravitational intensityList - II: (i) [L^2T^-2] (ii) [M^-1L^3T^-2] (iii) [LT^-2] (iv) [ML^2T^-2]Choose the corr… Answer: 3. (a) - (ii), (b) - (iv), (c) - (i), (d) - (iii) Find each dimension from its formula. (a) G=Fr²/m² : [M⁻¹L³T⁻²] , so (ii) (b) Pote... 1