Explanation

A valid assessment measures exactly what it is intended to measure.

It is of utmost importance to ensure the validity of an assessment in the fields of education and psychology as:

It guarantees that the results obtained are both meaningful and reliable.

The significance of a valid assessment lies in the following aspects:

1. Measuring Intended Constructs

2. Reliability

3. Avoiding Bias

4. Improving Decision-Making

Explanation

The given compound is an ionic compound

It is made up of:

• one potassium
• one manganese,
• four oxygen atoms.

Oxidation numbers of potassium (K) and oxygen (O) are +1 and -2 respectively.

Let us assume that the oxidation number of Mn is $x$.

Since ionic compounds are neutral, the net charge on them is zero.

(Oxidation number of K) + (Oxidation number of Mn) + (4 $\times$ The oxidation number of O) = $0$

(1)$\times$(K) + (1)$\times$(Mn) + 4$\times$(O) = $0$

$(1)$$\times$(+1) + (1)$\times$($x$) + 4$\times$(-2) = $0$

$x$ = +7

Hence, the oxidation number of $\text{Mn}$ in ${\text{KMnO}}_4$ is +7.

Explanation

The velocity of an electron is maximum in 1st shell

because according to Bohr's model

So we have velocity of electron = 2.188 ×10^6 m/s.

By calculation, we gained velocity= 1.094×10^6 m/s.

So it is determined that the velocity is decreased as we move from lower to higher shell

Explanation

Epistemology is a branch of philosophy that explores the nature, origin, and limitations of human knowledge

The term is derived from the Greek episteme (“knowledge”) and logos (“reason”),

It delves into:

• questions surrounding how we acquire knowledge,
• what constitutes knowledge
• how certain we can be about what we claim to know.
  

Explanation

"Extension Teaching" involves educators traveling to the student's location to provide personalized, hands-on instruction.

This teaching mode enhances:

• communication
• engagement
• learning outcomes.

Explanation

Grignard reagent reacts with water to give alkane.

This is because Grignard reagent acts as a strong base that reacts with the active hydrogen of water that is -H of  H2O  to form alkane as shown below :

Explanation

Boric acid on heating at 100oC gives HBO2.

On heating orthoboric acid (H3BO3) at 370 K or above,

It changes to metaboric acid (HBO2).

On further heating, this yields boric oxide B2O3.

Additional information:

Orthoboric acid, $H_{3}B{O}_3$ is a white crystalline solid, with soapy touch.

It is sparingly soluble in water but highly soluble in hot water.

Explanation

Methylated spirit is 10% methanol and 90% ethanol

The additives which are present in methanol makes it poisonous and dangerous.

This denatured alcohol is made for industrial purposes or non-drinking uses.  Methylated spirit is also used as a fuel for the burners

and it is also used as a solvent.

Explanation

GROUP - 11 (I B) [Copper, Silver and Gold]

Copper, Ag, and Au are known as coinage metals

Because they were used to make coins.

All the metals are noble w.r.t. chemical activity.

Explanation

I have not met her for a week.

میں ایک ہفتے سے اس سے نہیں ملا۔

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The word "for" is a preposition that is commonly used to express a period that has elapsed.

In this case, it shows how long it has been since the speaker last met the person mentioned.