<u>Answer:</u> The wavelength of spectral line is 656 nm
<u>Explanation:</u>
To calculate the wavelength of light, we use Rydberg's Equation:

Where,
= Wavelength of radiation
= Rydberg's Constant = 
= Final energy level = 2
= Initial energy level = 3
Putting the values in above equation, we get:

Converting this into nanometers, we use the conversion factor:

So, 
Hence, the wavelength of spectral line is 656 nm
Answer:
Explanation:
An internal force acts between elements of the system. Only external forces affect the motion of a system, according to Newton's first law. Newton's second law states that a net force on an object is responsible for its ... Prior to manned space flights, rocket sleds were used to test aircraft, missile equipment, and physiological
B.
Spring tides occur during a new/full moon. The sun, moon and earth form a straight line during these phases.
The relative molecular mass of acid A : 50 g/mol
<h3>Further explanation</h3>
Given
40.0 cm³(40 ml) of 0.2M sodium hydroxide
0.2g of a dibasic acid
Required
the relative molecular mass of acid A
Solution
Titration formula
M₁V₁n₁=M₂V₂n₂
n=acid/base valence(number of H⁺/OH⁻)
NaOH ⇒ n = 1
Dibasic acid = diprotic acid (such as H₂SO₄)⇒ n = 2
mol = M x V
Input the value in the formula :(1 = NaOH, 2=dibasic acid)
0.2 x 40 x 1 = M₂ x V₂ x 2
M₂ x V₂ = 4 mlmol = 4.10⁻³ mol ⇒ mol of Acid A
The relative molecular mass of acid A (M) :
