Answer:
A. 456 seconds
Explanation:
We are given that two students walk in the same direction along a straight path at a constant speed.
One student walks with a speed=0.90 m/s
second student walks with speed=1.9 m/s
Total distance covered by each students=780 meter
We have to find who is faster and how much time extra taken by slower student than the faster student.
Time taken by one student who travel with speed 0.90 m/s=
Time=
Time taken by one student who travel with speed 0.90 m/s
=
Time taken by one student who travel with speed 0.90 m/s
=866.6 seconds
Time taken by second student who travel with speed 1.9 m/s=
=410.5 seconds
The second student who travels with speed 1.9 m/s is faster than the student travels with speed 0.90 m/s .
Extra time taken by the student travels with speed 0.90 m/s=866.6-410.5=456.1 seconds
Extra time taken by the student travels with speed 0.90 m/s=456 seconds
Hence, option A is true.
The most important characteristics that are exhibited by metals are-
1- Metals are ductile
2-Most metals are conductive in nature.
3-Most metals are malleable.
4- Metals have strong inter molecular force of attraction between the.
5-Metals have luster.
6-Metals are sonorous.
Here we are given Tungsten filament.
Tungsten is a metal.So it must be conductive and as well as ductile in nature.
The electric filament that we are using in our electric bulb glows due to the heating effect of current.Hence the chosen substances for glowing electric bulb must have high melting point.
The melting point of tungsten is 1650 degree celsius which is very high.That's why it is used in electric bulb.
Hence the correct answer to the question is the third one i.e Tungsten is ductile,has a high melting point, and is electrically conductive.
Well a basic explanation is that some elements have enough electrons to be considered stable. These elements do not need to react with other elements to gain more electrons. Reactive elements are no where near stable; they respond with other elements in order to become stable. The more unstable, the harsher the reaction is.
