Answer:
c. A number and a unit
Explanation:
A scalar is a real number. We often use the term scalar in the context of vectors or matrices, to stress that a variable such as a is just a real number and not a vector or matrix.
Answer:
Explanation:
A physical quantity which can be completely described by the magnitude and direction both are called vector quantities. For example, displacement, velocity, etc.
A physical quantity which can be completely explained by the magnitude only is called scalar quantity. For example, mass, time, etc.
<u>Answer:</u>
<em>Equivalence point and end point are terminologies in pH titrations and they are not the same.
</em>
<u>Explanation:</u>
In a <em>titration the substance</em> added slowly to a solution usually through a pippette is called titrante and the solution to which it is added is called titrand. In acid-base titrations acid is added to base or base is added to acid.the strengths of the <em>acid and base titrated</em> determines the nature of the final solution.
At equivalence point the <em>number of moles of the acid</em> will be equal to the number of moles of the base as given in the equation. The nature of the final solution determines the <em>pH at equivalence point. </em>
<em>A pH less than 7 will be the result if the resultant is acidic and if it is basic the pH will be greater than 7. </em>In a strong base-strong acid and weak base-weak acid titration the pH at the equivalence point will be 7 indicating <em>neutral nature of the solution.
</em>
Answer;
The above statement is true.
-A photograph is taken by letting light fall on a light-sensitive medium, which then records the image onto that medium.
Explanation;
-A photograph is created when light is allowed to fall on a light-sensitive medium. The pattern of light creates an image that is recorded by the photographic device. How light or dark a photograph is depends on how much light was allowed to fall on the light-sensitive medium.
-A camera is a light-tight box that contains a light-sensitive material or device and a way of letting in a desired amount of light at particular times to create an image on the light-sensitive material.
<h2>The man have to apply force of 160 N</h2>
Explanation:
The work done to lift the bag of weight mg through height 2.5 m is 400 J
The work done can be found by relation W = mg x h
Thus mg = 
= 
= 160 N
Therefore the man have to apply the force of 160 N
