JEE Main Test 8

Result

JEE Main Test 8

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Weekly Quiz Competition

Question 1
4 / -1

Of the following which hydride is known as ‘hydroith’?

A
MgH₂

B
SrH₂

C
BeH₂

D
CaH₂

Solution

A salt-like binary compound (CaH2) used as a reducing agent and source of hydrogen is called Hydrolith.
Question 2
4 / -1

Directions: Assertion– Reason type questions. Each of these questions contains two statements; ,

Statement – 1 (Assertion) and ,

Statement – 2 (Reason) ,

Each of these questions also have four alternative choices, only one of which is the correct answer. You have to select the correct choice. ,

Que. Let A be a 2 × 2 matrix ,

Statement 1 : adj (adj A) = A ,

Statement 2 : |adj A| = |A|

A
Statement–1 is true, Statement–2 is true, Statement–2 is a correct explanation for statement–1

B
Statement–1 is true, Statement–2 is true; Statement–2 is not a correct explanation for statement–1

C
Statement–1 is true, statement–2 is false.

D
Statement–1 is false, Statement–2 is true

Solution

adj(adjA) = |A|^{n – 2}A, where |A| = determinant of A but n = 2 ⇒ A

also |adj A| = |A|^{n – 1}⇒ |A|

Statement–1 is true and Statement–2 is also true and Statement–2 is correct explanation of Statement–1

Hence, option A is correct.