Answer : (C) "Higher frequencies have larger spaces between lines".
Explanation:
In Young's experiment, the condition for constructive interference is given by :
.........(1)
n is order or number of lines observed
d is distance between slits
is the angle between the path and the line from screen to the slits.
We also know that, 
or

where,
c is the speed of light
is frequency
is wavelength
So, equation (1) turns into


So,

or
Higher frequencies have larger spaces between line.
So, correct option is (C).
Answer:
earth surface is uneven because land heats faster than water causes air to warm.,expand and rise over land while it cools and sinks over the cooler waters surface..
Answer: Option (B) is the correct answer.
Explanation:
It is known that for writing a chemical reaction equation, reactants are written on left hand side whereas products are written on right hand side.
And in between reactants and products a forward arrow is placed pointing towards the products.
Therefore, the reaction for carbon burns in the presence of oxygen to give carbon dioxide will be written as follows.

Here, carbon and oxygen atoms are the reactants whereas carbon dioxide is the product.
They are colourless solids (salts) that do not conduct electricity when solid, but conduct electricity in aqueous solution as the ions (that carry charge) are free to move.
They have a high melting point due to the strong electrostatic forces of attraction between oppositely charged ions
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