List of top Questions asked in CBSE CLASS XII

In a Young’s double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Determine the wavelength of light used in the experiment.

An aromatic compound ‘A’ on treatment with aqueous ammonia and heating forms compound ‘B’ which on heating with Br2 and KOH forms a compound ‘C’ of molecular formula C6H7N. Write the structures and IUPAC names of compounds A, B and C

The decomposition of A into product has value of k as \(4.5 \times  10^3 s^{-1}\) at \(10°C\) and energy of activation \(60\  kJ mol^{-1 }\). At what temperature would k be \(1.5 \times  10^4 s^{-1}\)?

A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is
(i) doubled
(ii) reduced to half?

Find a particular solution satisfying the given condition: \(\frac {dy}{dx}+2y\ tan\ x=sin\ x;\ y=0\  when \ x=\frac \pi3\)

Find general solution: \((x+3y^2) \frac {dy}{dx} = y,\  (y>0)\) 

In a culture,the bacteria count is 1,00,000.The number is increased by \(10\%\) in 2 hours. In how many hours will the count reach 2,00,000,if the rate of growth of bacteria is proportional to the number present?
In a bank,principal increases continuously at the rate of \(5\%\) per year. An amount of Rs1000 is deposited with this bank,how much will it worth after 10years\((e^{0.5}=1.648)\).
In a bank principal increases continuously at the rate of \(r\%\) per year.Find the value of \(r\) is Rs100 doubles itself in 10years\((log_e2=0.6931).\)
At any point \((x,y)\) of a curve,the slope of a tangent is twice the slope of the line segment joining the point of contact to the point \((-4,-3)\).Find the equation of the curve given that it passes through \((-2,1)\).
Find the equation of a curve passing through the point \((0,-2)\) given that at any point \((x,y)\) on the curve,the product of the slope of its tangent and y-coordinate of the point is equal to the x-coordinate of the point.

Find the equation of the curve passing through the point \((0,\frac \pi4) \)whose differential equation is, \(sin\ x cos \ y\ dx+cos\ xsin\  y\ dy=0\)

Find the equation of a curve passing through the point \((0,2)\) given that the sum of the coordinates of any point on the curve exceeds the magnitude of the slope of the tangent to the curve at that point by 5.
For the differential equations, find a particular solution satisfying the given condition:\(cos(\frac{dy}{dx})=α(α∈R);y=1\) when x=0
For the differential equations, find the general solution: \(x^5\frac{dy}{dx}=-y^5\)
For the differential equations , find the general solution:\(\frac {dy}{dx}+y=1, \ \ (y≠1)\)
For the differential equations, find the general solution:\(\frac{dy}{dx}=\frac{1-cosx}{1+cosx}\)
The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?
The work function of caesium metal is \(2.14 eV\). When light of frequency \(6×1014Hz\) is incident on the metal surface,photoemission of electrons occurs. What is the
(a)maximum kinetic energy of the emitted electrons, 
(b)Stopping potential, and
(c)maximum speed of the emitted photoelectrons?

Four point charges \(q_A\)\( = 2 µC\), \(q_B\) \(= −5 µC\), \(q_C\) = 2 µC, and \(q_D\) \(= −5 µC\) are located at the corners of a square ABCD of side 10 cm. What is the force on a charge of 1 µC placed at the centre of the square?

If A=\(\begin{bmatrix}1&1&-2\\2&1&-3\\5&4&-9\end{bmatrix}\),find IAI.

Compare the stability of +2 oxidation state for the elements of the first transition series

What is the 'sadness' that the poet refers to in the poem?
What does the title of the poem suggest to you? What do you think the poem is about?
Why has the poet brought in the image of the merry children 'spilling out of their homes'?