Answer:
Explanation:
Given
Overall magnification 
One lens magnification is 
suppose the magnification of other lens is 
A compound lens is made up of series of lenses either of same or of different magnification so
is given by
If lens is replaced by 
lens then total magnification is
In series circuit, Req = R₁ + R₂ + R₃ + ···
In parallel circuit, 
<h3>Q7.</h3>
total resistance in the upper branch = R₂ + R₃ = R₂ + 2
R₂ + 2 = 12
R₂ = 10Ω
<h3>Q8.</h3>
Req = 1.7Ω
Map scale<span> refers to the relationship (or ratio) between distance on a </span>map<span> and the corresponding distance on the ground. For example, on a 1:100000 </span>scale map<span>, 1cm on the </span>map<span> equals 1km on the ground.</span>
Answer:
20.1 eV.
Explanation:
Energy of n the orbital of a hydrogen like atom in eV having atomic no Z is given by the relation
Eₙ = -Z² x 13.6 / n² eV
For B⁴⁺ , Z = 5.
For B⁴⁺ having only one electron ( like hydrogen ) energy of n=5 orbital
E₅ = - 5² X 13.6 / 5² = - 13.6 eV.
And for n = 3
E₃ = - 5² X 13.6 / 3²
= - 37.77 eV.
Difference = 33.77-13.6 = 20.17 eV.
Light energy will be emitted when electron transits from n = 5 to n = 3. The light will have energy equal to the difference of energy of 20.1 eV.
