Calculate the wave number for the longest wavelength transition in the Balmer series of atomic hydrogen.
According to Balmer formula
ṽ=1/λ = RH[1/n12-1/n22]
For the Balmer series, ni = 2.
Thus, the expression of wavenumber(ṽ) is given by,
Wave number (ṽ) is inversely proportional to wavelength of transition. Hence, for the longest wavelength transition, ṽ has to be the smallest.
For ṽ to be minimum, nf should be minimum. For the Balmer series, a transition from ni = 2 to nf = 3 is allowed. Hence, taking nf = 3,we get:
ṽ= 1.5236 × 106 m–1
Popular Questions of Class 11th chemistry
- Q:-
A sample of drinking water was found to be severely contaminated with chloroform, CHCl3, supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).
(i) Express this in percent by mass.
(ii) Determine the molality of chloroform in the water sample.
- Q:-
Calculate the amount of carbon dioxide that could be produced when
(i) 1 mole of carbon is burnt in air.
(ii) 1 mole of carbon is burnt in 16 g of dioxygen.
(iii) 2 moles of carbon are burnt in 16 g of dioxygen.
- Q:-
Write the general outer electronic configuration of s-, p-, d- and f- block elements.
- Q:-
Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% dioxygen by mass.
- Q:-
Calculate the wavelength, frequency and wave number of a light wave whose period is 2.0 × 10–10 s.
- Q:-
Calculate the mass percent of different elements present in sodium sulphate (Na2SO4).
- Q:-
In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.
(i) 300 atoms of A + 200 molecules of B
(ii) 2 mol A + 3 mol B
(iii) 100 atoms of A + 100 molecules of B
(iv) 5 mol A + 2.5 mol B
(v) 2.5 mol A + 5 mol B
- Q:- The equilibrium constant for a reaction is 10. What will be the value of ΔG0 ? R = 8.314 JK–1 mol–1, T = 300 K.">
The equilibrium constant for a reaction is 10. What will be the value of ΔG0 ? R = 8.314 JK–1 mol–1, T = 300 K.
- Q:-
Calculate the mass of sodium acetate (CH3COONa) required to make 500 mL of 0.375 molar aqueous solution. Molar mass of sodium acetate is 82.0245 g mol–1
- Q:-
A welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives 3.38 g carbon dioxide, 0.690 g of water and no other products. A volume of 10.0 L (measured at STP) of this welding gas is found to weigh 11.6 g. Calculate
(i) empirical formula,
(ii) molar mass of the gas, and
(iii) molecular formula.
Recently Viewed Questions of Class 11th chemistry
- Q:- When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.">
When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.
- Q:- ) of the yellow light.">
Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm. Calculate the frequency (ν) and wave number (
) of the yellow light. - Q:-
A certain particle carries 2.5 × 10–16C of static electric charge. Calculate the number of electrons present in it.
- Q:-
What sorts of informations can you draw from the following reaction ?
(CN)2(g) + 2OH-(aq) → CN-(aq) + CNO-(aq) + H2O(l)
- Q:-
Express the following in the scientific notation:
(i) 0.0048
(ii) 234,000
(iii) 8008
(iv) 500.0
(v) 6.0012 - Q:- What is the relationship between the members of following pairs of structures? Are they structural or geometrical isomers or resonance contributors?
(a)
(b)
(c)
">
What is the relationship between the members of following pairs of structures? Are they structural or geometrical isomers or resonance contributors?
(a)
(b)
(c)
- Q:-
ΔU0of combustion of methane is – X kJ mol–1. The value of ΔH0 is
(i) = ΔU0
(ii) > ΔU0
(iii) < ΔU0
(iv) = 0
- Q:-
What is the maximum number of emission lines when the excited electron of an H atom in n = 6 drops to the ground state?
- Q:-
Explain the formation of H2 molecule on the basis of valence bond theory.
- Q:- A reaction, A + B → C + D + q is found to have a positive entropy change. The reaction will be
(i) possible at high temperature
(ii) possible only at low temperature
(iii) not possible at any temperature
(iv) possible at any temperature
">A reaction, A + B → C + D + q is found to have a positive entropy change. The reaction will be
(i) possible at high temperature
(ii) possible only at low temperature
(iii) not possible at any temperature
(iv) possible at any temperature
10 Comment(s) on this Question
Thanks
Thanks
Thnku it hepled a lot..
This is correct ans
Wait then value is 1.097.isit right
Very specific and precise answer .
Thnx a lot...it was best last minute tip I ever recieved
Change the background the answer was quite helpful
salute to this question.
Thanks a lot. It was very helpful.please change the background
- NCERT Chapter