List of top Questions asked in CBSE CLASS XII

For what values of x,\(\begin{bmatrix} 1 & 2 & 1 \end{bmatrix}\)\(\begin{bmatrix} 1 & 2 & 0\\ 2 & 0 & 1 \\1&0&2 \end{bmatrix}\)\(\begin{bmatrix} 0 \\2\\x\end{bmatrix}\)=O?

Find the inverse of each of the matrices,if it exists \(\begin{bmatrix} 2 & 1 \\ 7 & 4 \end{bmatrix}\)

What is the Planning Process?

Find the inverse of each of the matrices,if it exists. \(\begin{bmatrix} 2 & 3\\ 5 & 7 \end{bmatrix}\)

Find the inverse of each of the matrices, if it exists. \(\begin{bmatrix} 1 & 3\\ 2 & 7\end{bmatrix}\)

If A'= \(\begin{bmatrix} 3 & 4 \\ -1 & 2 \\ 0 &1 \end{bmatrix}\)\(\begin{bmatrix} -1 & 2 & 1 \\ 1 &2 & 3\end{bmatrix}\) , then verify that
(i) \((A+B)'=A'+B' \)
(ii) \((A-B)'=A'-B'\)

If (i) A=\(\begin{bmatrix} \cos\alpha & \sin\alpha\\ -\sin\alpha & \cos\alpha \end{bmatrix}\),then verify that A'A=I
(ii) A= \(\begin{bmatrix} \sin\alpha & \cos\alpha\\ -\cos \alpha & \sin\alpha \end{bmatrix}\),then verify that A'A=I

Let A=\(\begin{bmatrix} 0 & 1 \\ 0 & 0 \end{bmatrix}\),show that(aI+bA)ⁿ=aⁿI+na^n-1bA,where I is the identity matrix of order 2 and n∈N

Evaluate \(\begin{vmatrix} cos\alpha cos\beta &cos\alpha sin\beta &-sin\alpha \\ -sin\beta&cos\beta &0 \\ sin\alpha cos\beta&sin\alpha\sin\beta &cos\alpha \end{vmatrix}\)

Find the vector and the cartesian equations of the lines that pass through the origin and(5,-2,3).

How did the instructor “build a swimmer” out of Douglas?

In spite of all the rationality that human beings are capable of, most of us are suggestible and yield to archaic superstitions.

Write the Nernst equation and emf of the following cells at 298 K :
(i) Mg(s) | Mg²⁺ (0.001M) || Cu²⁺(0.0001 M) | Cu(s)
(ii) Fe(s) | Fe²⁺ (0.001M) || H⁺ (1M)|H₂(g)(1bar) | Pt(s)
(iii) Sn(s) | Sn²⁺(0.050 M) || H⁺ (0.020 M) | H₂(g) (1 bar) | Pt(s)
(iv) Pt(s) | Br₂(l) | Br^- (0.010 M) || H⁺ (0.030 M) | H₂(g) (1 bar) | Pt(s).

The people in this story suddenly realise how precious their language is to them. What shows you this? Why does this happen?

How would you account for the following:

Of the d⁴ species, Cr²⁺ is strongly reducing while manganese(III) is strongly oxidising.
Cobalt(II) is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised.
The d¹ configuration is very unstable in ions.

What is oogenesis? Give a brief account of oogenesis.

What is the kind of pain and ache that the poet feels?

What are the ‘ordeals’ Aunt Jennifer is surrounded by, why is it significant that the poet uses the word ‘ringed’? What are the meanings of the word ‘ringed’ in the poem?

Is Saheb happy working at the tea-stall? Explain.

“All we have to fear is fear itself”. Have you ever had a fear that you have now overcome? Share your experience with your partner.

There are moments in life when we have to make hard choices between our roles as private individuals and as citizens with a sense of national loyalty. Discuss with reference to the story you have just read.

Give three hypotheses for explaining why tropics show greatest levels of species richness.

The actual pain or inconvenience caused by a physical impairment is often much less than the sense of alienation felt by the person with disabilities. What is the kind of behaviour that the person expects from others?

Write down the electronic configuration of:
(i) Cr³⁺ (iii) Cu⁺ (v) Co²⁺ (vii) Mn²⁺
(ii) Pm³⁺ (iv) Ce⁴⁺ (vi) Lu²⁺ (viii) Th⁴⁺