List of top Questions asked in CBSE CLASS XII

Observe the schematic representation of assisted reproductive technology given below: 
 


Identify the most appropriate technique depicted in the above diagram. 
 

A phenomenon where a male insect mistakenly identified the patterns of a flower as the female insect partner, and tries to copulate and thereby pollinates the flower is said to be:
Which one of the following statements is correct in the context of observing DNA separation by agarose gel electrophoresis?

Study the pedigree chart of a family showing the inheritance pattern of a certain disorder. Select the option that correctly identifies the nature of the trait depicted in the pedigree chart: 
 

Identify the correct labellings in the figure of a fertilised embryo sac of an angiosperm given below:

Which one of the following chromosomal events will not result in genetic variation amongst the offspring?
A person with trisomy of the 21st chromosome shows:
(i) Furrowed tongue
(ii) Characteristic palm crease
(iii) Rudimentary ovaries
(iv) Gynaecomastia
Select the correct option from the choices given below:
(b) In which condition will the pyramid remain always upright?
(a) “Mother’s milk is considered very essential for the new born infant.” Justify.
How does latitude influence the species richness of an ecosystem?
State why plant breeders are interested in artificial hybridisation programme. How do they carry out this process?
(a) What are transgenic animals?
(b) Name the transgenic animal having the largest number amongst all the existing transgenic animals.
(b) Mention what does ‘K’ in the graph represent.
Assertion (A): In molecular diagnosis, single stranded DNA or RNA tagged with radioactive molecule is called a probe.
Reason (R): A probe always searches and hybridises with its complementary DNA in a clone of cells.
Given \[ \frac{d}{dx} F(x) = \frac{1}{\sqrt{2x - x^2}} \] and \( F(1) = 0 \), find \( F(x) \).
Let \[ A = \begin{bmatrix} a & b \\ c & d \end{bmatrix} \] be a square matrix such that \[ \text{adj } A = A. \] Then, \( (a + b + c + d) \) is equal to:
If \[ \begin{bmatrix} 1 & 3 & 1 \\ k & 0 & 1 \\ 1 & 0 & 1 \end{bmatrix} \] has a determinant of \( \pm 6 \), then the value of \( k \) is:
Of the following, which group of constraints represents the feasible region given below?
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If \[ A = \begin{bmatrix} 2 & 0 & 0 \\ 0 & 3 & 0 \\ 0 & 0 & 5 \end{bmatrix}, \] then \( A^{-1} \) is:
If \( x = e^{y^2} \), prove that \[ \frac{dy}{dx} = \frac{\log x - 1}{(\log x)^2}. \]
Check the differentiability of \( f(x) \) at \( x = 1 \), where: \[ f(x) = \begin{cases} x^2 + 1, & 0 \leq x < 1, \\ 3 - x, & 1 \leq x \leq 2. \end{cases} \]
Find the value of \( a \) and \( b \) so that the function \( f \) defined as: \[ f(x) = \begin{cases} \frac{x - 2}{|x - 2|} + a, & x < 2, \\ a + b, & x = 2, \\ \frac{x - 2}{|x - 2|} + b, & x > 2, \end{cases} \] is a continuous function.
Find the intervals in which the function \[ f(x) = \frac{\log x}{x} \] is strictly increasing or strictly decreasing.
Find the absolute maximum and absolute minimum values of the function \[ f(x) = \frac{x^2}{2} + \frac{2}{x} \] on the interval \( [1, 2] \).