All questions

• The position vector of a moving particle at time t is r=3i+4t^2j-t^3k .. Its displacement during the time interval t=1 s to t=3 s is Correct answer is 32j-26k Explaination:: r=3i+4t²j-t³k r_(t=1s)=3i+4j-k r_(t=3s)=3i+36j-27k Displacement = (r_(t=3s))-(r_(t=1s)) = 32j-26k Physics 1 answer
• If a unit vector is represented by 0.5i +0.8 j ​+ck then the value of 'c' is Correct option is b) √(0.11) Explaination:: The unit vector is given as A=0.5i +0.8 j +ck Magnitude of unit vector is always equal to 1 √((0... Physics 1 answer
• The area of the region bounded by the curve y = 2x – x2 and x – axis is Correct answer is 4/3sq.units Explaination:: Given curve is y =2 x-x² or (x-1)² =-(y-1) The curve cut the x -axis at (0,0) and (2,0) . there... Mathematics 1 answer
• The point on the curve 6y = x3 + 2 at which y – co-ordinate is changing 8 times as fast as x– co-ordinate is ______________ Correct answer is option A){4,11} Mathematics 2 answers
• The joint equation of bisectors of angles between lines x = 5 and y = 3 is ___________ Answer: B) x² - y² - 10x + 6y + 16 = 0 The lines x = 5 (vertical) and y = 3 (horizontal) are perpendicular and meet at (5, 3) . Their angle... Mathematics 1 answer
• Derivative of log (secθ + tanθ ) with respect to secθ at θ = π/4 is ____________ Answer: B) 1 Let u = log(secθ + tanθ) and v = secθ . Differentiate both with respect to θ . du/dθ = fracsecθtanθ + sec²θsecθ + tanθ The nume... Mathematics 1 answer
• In Δ ABC (a – b)2 cos2 2 c + (a + b)2 sin2 2 c = Correct answer is C² https://youtu.be/l-lf4ykAdtk Instead of pythagoras You can use this formulas cos(C) = a² + b² − c²over 2ab Mathematics 1 answer
• If r.v. X : waiting time in minutes for bus and p.d.f. of X is given by The correct answer is option b) 0.8 f(x)= \1/5,/0, \ \ 0≤ x≤ 5, /otherwise, Solution will come soon Mathematics 1 answer
• Three identical masses m are kept at the vertices of equilateral Δ of side ‘a’. Answer is sqrt3 Gm²/a² Physics 1 answer
• The sum of two numbers is 128 and their difference is 16. Find the numbers. Let the two numbers be x and y According to 1^st condition , x+y=128 ------1 According to 2nd condition , x-y=16 --------2 Adding equation 1... Hots 1 answer
• 5 Chairs and 4 Tables Together Cost ₹5600, While 4 Chairs and 3 Tables Together Cost ₹ 4340. Find the Cost of Each Chair and that of Each Table Video solution:: https://youtu.be/mG1XSNDtBig Text Solution Let the cost of a chair be ₹ x and that of a table be ₹ y, then 5x + 4y = 5600 …... Hots 1 answer
• 5 books and 7 pens together cost Rs 79 whereas 7 books and 5 pens together cost Rs 77, find the total cost of 1 book and 2 pens. Let the cost of a book be Rs x and that of a pen be Rs y. Then, 5x + 7y = 79 .....(i) 7x + 5y = 77 ....(iii) Multiplying equation (i) by 5 a... Hots 1 answer
• Shabana’s age 10 year hence will be twice as Juhi’s present age. The correct answer is shabanas age is 26 years and juhis age is 18 years Video solution::: https://youtu.be/g0836O7_m4A Hots 1 answer
• Uncertainty in position of a particle of 25 g in space is 10–5 m. Hence, uncertainty in velocity (m s–1) is (Planck’s constant, h = 6.6 × 10–34 Js) Correct option is (a) 2.1 × 10^(–28) Explaination:: mass=25g=25 × 10⁻³ kg , Δx=10⁻⁵m According to Heisenberg uncertainty principle triangle... Random 1 answer
• In a hydrogen atom, if the energy of an electron in the ground state is – 13.6 eV, then that in the 2nd excited state is Answer: −1.51 eV For hydrogen the energy of the n th orbit is E_n = -frac13.6n²\ eV The ground state is n = 1 , the first excited state is n... Random 1 answer
• Which of the following ions has the maximum magnetic moment ? Correct option is (a) Mn²⁺ Explaination ::: number of unpaired electrons in Mn²⁺ =5 number of unpaired electrons in Fe²⁺ =4 number of unpair... Random 1 answer
• Energy of H-atom in the ground state is –13.6 eV, hence energy in the second excited state is Correct answer is option (c) –1.51 eV Explaination:: 2 ^nd\ excited \ state \ n=3 E n =− 13.06/n² -By formula E₃=-13.06/3²=-13.06/9 = -1.51... Random 1 answer
• Identify from the following reactions the reactants that undergo oxidation and reduction A. Fe + S → FeS Here , Fe is oxidised from 0 to +2, while S is reduced from 0 to -2 Fe undergoes oxidation (as losing electrons) Sulphur und... Chemical reactions and equations 1 answer
• 5. Observe the following picture a write down the chemical reaction with explanation. The picture given shows the corrosion of iron. The chemical formula of rust is Fe₂O₃.H₂O. The rust on iron does not form by a simple reactio... Chemical reactions and equations 1 answer
• d. It is recommended to use air tight container for storing oil for long time It is recommended to use air tight container for storing oil for long time because, When oil comes in contact with air, it undergoes oxidati... Chemical reactions and equations 1 answer
• c.While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to... Chemical reactions and equations 1 answer
• b. It takes time for pieces of Shahabad tile to disappear in HCl, but its powder disappears rapidly When HCl is added to Shahabad stone effervescence of CO₂ is formed. The CO₂effervescence is formed slowly with the pieces of Shahabad tiles... Chemical reactions and equations 1 answer
• a.When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky i. When limestone (CaCO₃) is heated; it undergoes decomposition reaction giving calcium oxide (CaO) and carbon dioxide (CO₂) as products. ii... Chemical reactions and equations 1 answer
• d. Displacement reaction 3. Explain the following terms with examples. The reaction in which the place of the ion of a less reactive element in a compound is taken by another more reactive element by formation o... Chemical reactions and equations 1 answer