Doubtly
@Doubtly · Joined Feb 2021
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- a) What problems did Brazil and India face after independence? Q2 There were many common problems that Brazil and India faced after independence. Some of them are: management – The resources of both the cou... 1
- Q 1) Are the sentences right or wrong. ? Rewrite the wrong ones (a) Brazil is mainly located in the Southern Hemisphere. Answer: Right (b) Tropic of Capricorn passes through the middle of India. Answer: W... 1
- Crystals can be classified into _______ basic crystal units. (A) 3 (B) 7 (C) 14 (D) 4 B) 7 is the correct option Crystals can be classified into 7 basic crystal units. 1
- Which of the following is a crystalline solid? (A) Glass (B) Rubber (C) Plastic (D) Sugar Correct option is D Sugar Sugar is a crystalline solid while glass, rubber and plastic are amorphous solids. 1
- Amorphous solids are _______. (A) true solid substances (B) substances with ordered (c)super cooled liquids is correct option : Amorphous solids are super cooled liquids 1
- Amorphous solids _______. (A) possess sharp melting points (C) is the correct option Amorphous solids do not undergo clean cleavage when cut with knife 1
- A solid having irregular shape is called _______ solid (A) amorphous is correct answer: A solid having irregular shape is called amorphous solid 1
- The ability of crystalline solids to change values of physical properties when measured in different directions is called _______. C) Anisotropy is correct answer : The ability of crystalline solids to change values of physical properties when measured in different direc... 1
- Graphite, diamond and fullerene are the polymorphic forms of _______. B) Carbon is the correct option 2
- Which among the following solids is NOT soft? Copper among the following solids is NOT soft 2
- A student measured the length of a rod and wrote it as 3.50 cm. Which instrument did he use to measure it? Measured length of rod = 3.50 cm That means least count of the measuring instrument should be 0.01 cm = 0.1 mm For vernier scale 1 main scal... 1
- Let E0 denote the dimensional formula of the permittivity of vacuum. If M = mass, L = length, T = time and A = electric current, then: Correct option is B From Coulomb's law we know, F = 1 over 4π in ₀q₁q₂ over r² therefore in ₀ = 1 over 4π q₁q₂ over Fr² Hence, [ in ₀ ] = [... 1
- Resistance of a given wire is obtained by measuring the current flowing in it and the voltage difference applied across it. If the percentage Correct option is A) 6% We know R = V over I thereforeΔ R over R = Δ V over V + Δ I over I Percentage error in R = Δ R over R × 100 = Δ V ov... 1
- The respective number of significant figures for the numbers 23.023, 0.0003 and 2.1 10–3 are Corret option is 1) 5,1,2 23.023 has 5 significant figures. 0.0003 has 1 significant figure. 2.1 × 10^(–3) has 2 significant figures. 1
- A body of mass m = 3.513 kg is moving along the x-axis with a speed of 5.00 ms−1. The magnitude of its momentum is recorded as Momentum, p = m × v = 3.513 × 5.00 = 17.565 kg m/s = 17.6 kg m/s Here number of significant digits in m is 4 and in v is 3, so, p must have... 1
- The dimension of magnetic field in M, L, T and C (coulomb) is given as Correct option is C) MT⁻¹C⁻¹ We know that, Lorentz force | overrightarrow F | = | qoverrightarrow v × overrightarrow B | therefore [B]=[F] o... 1
- Out of the following pair, which one does NOT have identical dimensions is A angular momentum and Planck's constant Correctt option is C) moment of inertia and moment of a force Moment of inertia, I = Mr² therefore [I] = [ML²] Moment of force, overrightarr... 1
- Which one of the following represents the correct dimensions of the coefficient of viscosity? option 1 is correct From stokes law, Viscous force F = 6π η rv ⇒ η = F over 6π rv therefore[η] = [MLT^(- 2)] over [L][LT^(- 1)] ⇒ [η] = [ML^... 1