please help!!!!!what is the main function of a telescope? A.it brings scientists closer to distant obejects B. it magnifies ligh
2 answers:
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Answer:
Explanation:
Given:
- wavelength of light in the air,
- time taken to travel from the source to the photocell via air,
- time taken to reach the photocell via air and glass slab,
- thickness of the glass slab,
<u>Now we have the relation for time:</u>
hence,
c= speed of light in air
For the case when glass slab is inserted between the path of light:
(since light travel with the speed c only in the air)
here:
v = speed of light in the glass
Using Snell's law:
Answer: D. The elements have the same number of valence electrons
Explanation: The chemical reactivity of elements is governed by the valence electrons present in the element.
The elements present in the same group or vertical column have similar valence configurations and thus behave similarly in chemical reactions or have similar bonding properties.
For Example: Both fluorine and chlorine belong to same family or group and both have 7 electrons in their valence shell and thus accept single electron to attain noble gas configuration.
thus both would bond with a cation bearing a single positive charge.