Answer:
A

B

Explanation:
From the question we are told that
The wavelength is
The angle of first bright fringe is
The order of the fringe considered is n =1
Generally the condition for constructive interference is
=> 
=> 
Converting to cm

Generally the number of grating pre centimeter is mathematically represented as

=> 
=> 
Considering question B
From the question we are told that
The first wavelength is
The second wavelength is
The order of the fringe is 
The grating is 
Generally the slit width is mathematically represented as

=> 
=> 
Generally the condition for constructive interference for the first ray is mathematically represented as
=>
=> ![\theta_1 = sin^{-1} [\frac{ 2 * 650 *10^{-9} }{ 2*10^{-6}}]](https://tex.z-dn.net/?f=%5Ctheta_1%20%3D%20sin%5E%7B-1%7D%20%5B%5Cfrac%7B%202%20%2A%20%20%20650%20%2A10%5E%7B-9%7D%20%7D%7B%202%2A10%5E%7B-6%7D%7D%5D)
=> 
Generally the condition for constructive interference for the second ray is mathematically represented as
=>
=> ![\theta_2 = sin^{-1} [\frac{ 2 * 420 *10^{-9} }{ 2*10^{-6}}]](https://tex.z-dn.net/?f=%5Ctheta_2%20%3D%20sin%5E%7B-1%7D%20%5B%5Cfrac%7B%202%20%2A%20%20%20420%20%2A10%5E%7B-9%7D%20%7D%7B%202%2A10%5E%7B-6%7D%7D%5D)
=> 
Generally the angular separation is mathematically represented as

=> 
=> 
Answer:
I think its B but I may be wrong
Answer:
Diamagnetic
Explanation:
Hunds rule states that electrons occupy each orbital singly first before pairing takes place in degenerate orbitals. This implies that the most stable arrangement of electrons in an orbital is one in which there is the greatest number of parallel spins(unpaired electrons).
For vanadium V ion, there are 18 electrons which will be arranged as follows;
1s2 2s2 2p6 3s2 3p6.
All the electrons present are spin paired hence the ion is expected to be diamagnetic.
let Coefficients of Friction of Rubber on asphalt (dry) =0.7
F= Coefficients of Friction * normal force = 0.7 * 60 =42 N
so the net force of the rubber is zero, meaning it will travel at a constant speed.
When the rubber is travel at 2m/s, 42N is required to keep moving at constant speed