A) State the meaning of the term principal focus as applied in lenses.
1 answer:
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Answer:
They can travel in a vacuum.
Explanation:
» Only electromagnetic waves travel through vacuum. The other mechanical waves require a material medium to travel.
Answer:
λ = 470.66 nm
Explanation:
for bright fringe
D= distance between slit and screen
d= distance between the slits
for first order bright fringe m = 1,
for dark fringe,we have
Now to get the dark fringes at the same location we should have;
(706)D/d = (m + 1/2)λD/d
put m = 1
(1 + 1/2)λ = (706)
λ = 470.66 nm
By holding a positive charge and there are positive charges of equal magnitude 1 m to your north and 1 m to your east. Therefore, the direction of the force on the charge you are holding will be to the southwest.
Let I hold the charge , q at the centre of given co-ordinate system and two positive charge of equal magnitude Q are placed 1 m to my North and 1 m to my South .
now, both the charge are same nature e.g., positive . Let my charge is also positive (well, you can assume negative too , I am considering positive because it makes me easy to solve) then, both charge repel to my charge.
charge Q placed on east is repelling my charge q toward west . similarly charge Q placed on North is repelling my charge q toward south.
Now , use vector for solve it.
vector = vector Fe + vector Fn,
⇒ || =
⇒ Fe = Fs = KqQ/(1m)² = KqQ
⇒ = √{Fe² + Fs²} = √{(kqQ)²+(KqQ)²}
⇒ = √2KqQ
Hence, net force act on q {my charge } is √2KqQ and the direction of force is S - W (southwest )direction.
To learn more about positive charges here
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