Doubtly
@Doubtly · Joined Feb 2021
- Answers
- 3,792
- Questions
- 8,007
- Upvotes received
- 435
- For what value of displacement the kinetic energy and potential of a simple harmonic oscillation become equal ? The correct option is (3) x= ±Aoversqrt2 Explaination:: potential energy = 1over2kx²=1over2mω²( x²) Kinetic energy = 1over2m(ω√( A²-x²))² As... 1
- Which of the following polymer is used in the manufacture of wool laminates ? The correct answer is option (1) Urea formaldehyde resin Explanation:: 1
- The green house gas/es is (are : (A) Carbon dioxide (B) Oxygen (C) Water vapour (D) Methane (1) (A), (C) and (D) only The green house gases are CO_(2 ), H₂O(vapour) & CH₄ 1
- The equivalents of ethylene diamine required to replace the neutral ligands from the coordination 2 is the correct answer for this question [Co(NH₃)₄Cl₂]Cl + 2en → [Co(en)₂Cl₂]Cl + 4NH₃ 1
- Complete combustion of 750 g of an organic compound provides 420 g of CO2 and 210 g of H2O. 3 is the answer . This is a Liebeig method for estimation of carbon and H-percentage % of H-element . 1
- A certain element crystallises in a bcc lattice of unit cell edge, length 27ºÅ. If the same element Answer: 33 Explanation:: for bcc structure 4r=sqrt3a r=sqrt3aover4 …1 For FCC structure 4r=sqrt2a r=sqrt2aover4 …2 From 1 and 2 1
- The type pollution that gets increased during the day time and in the presence of O3 is : (2) Oxidising smog In presence of ozone(O3), oxidising smog gets increased during the day time because automobiles and factories produce mai... 1
- Which of the following reaction DOES NOT involve Hoffmann bromamide degradation ? The correct answer is option 3) This reaction does not involve haffmann bromanide degradation Rest all options involve haffmann bromamide de... 1
- The process that involves the removal of sulphur from the ores is : jee main march 2021 1) roasting Removal of sulphur from the ore is done by Roasting. 1
- Which among the following pairs of Vitamins is stored in our body relatively for longer duration ? (2) Vitamin A and Vitamin D 2
- In chromatography technique, the purification of compound is independent of : Correct answer is option (2) Physical state of the pure compound In chromotography technique, the purification of a compound is independent... 1
- Which of the following is Lindlar catalyst ? (1) Cold dilute solution of KMnO4 (2) Partially deactivated palladised charcoal 2
- In thermodynamics, heat and work are : (1) Extensive thermodynamic state variables (2) Point functions (3) Path functions The correct answer is option 3) path function 2
- One main scale division of a vernier callipers is 'a' cm and nth division of the vernier scale coincide with (n – 1)th The correct answer is option D) 10aover n Explanation:: 1
- A 25 m long, antenna is mounted on an antenna tower. The height of the antenna tower is 75 m. The correct answer is option 3) 100 m Explanation: height of antenna= λover 4 25= λover 4 λ=100 1
- The maximum and minimum distances of comet from the Sun are 1.6 × 1012 m and 8.0 × 1010 m respectively The correct answer is option A) 3.0×10³ m/s Explanation:: L=mv₁r₁=mv₂r₂ V₂= v₁r₁over r₂ =v₁ 8×10¹⁰over 160×10¹⁰ =6×10⁴over 20 =3000 m/s 1
- 22 Ne nucleus, after absorbing energy, decays into two α-particles and an unknown nucleus. The unknown nucleus is The correct answer is option B) carbon Explanation:: ²²Ne decays α particle = He²⁺ Mass No = 4 p=2,n=2 So, New mass no. =22−8=14 Atomic No.... 1
- Which of the following statement(s) is (are) correct ? (A) The rest mass of a stable nucleus is less than the The correct answer is option A ) The rest mass of a stable nucleus is less than the sum of the rest masses of its separated nucleons. 2