MCQ
The wavelength of light emitted from second orbit to first orbits in a hydrogen atom is
- ✓$1.215 \times 10^{-7} m$
- B$1.215 \times 10^{-5} m$
- C$1.215 \times 10^{-4} m$
- D$1.215 \times 10^{-3} m$
✓
Answer
Correct option: A.
$1.215 \times 10^{-7} m$
Energy radiated $E=10.2 \mathrm{eV}=10.2 \times 1.6 \times 10^{-19} \mathrm{~J}$
$\Rightarrow E=\frac{h c}{\lambda} \Rightarrow \lambda=1.215 \times 10^{-7} \mathrm{~m}$
$\Rightarrow E=\frac{h c}{\lambda} \Rightarrow \lambda=1.215 \times 10^{-7} \mathrm{~m}$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A steel ball of radius $2 \mathrm{~cm}$ is at rest on a frictionless surface. Another ball of radius $4 \mathrm{~cm}$ moving at a velocity of $81 \mathrm{~cm} / \mathrm{sec}$ collides elastically with first ball. After collision the smaller ball moves with speed of
→The diode shown in the circuit is a silicon diode. The potential difference between the points $A$ and $B$ will be
→Out of the following which quantity does not depend on path
A body moves from rest with a constant acceleration. Which one of the following graphs represents the variation of its kinetic energy $K$ with the distance travelled $x$ ?
→The patient is asked to drink $\mathrm{BaSO}_4$ for examining the stomach by $X$-rays because $X$-rays are
→$V_{-i}$ graphs for parallel and series combination of two identical resistors are as shown in figure. Which graph represents parallel combination
→
The direction of the null points is on the equatorial line of a bar magnet, when the north pole of the magnet is pointing
The velocity of water waves $v$ may depend upon their wavelength $\lambda$, the density of water $\rho$ and the acceleration due to gravity $g$. The method of dimensions gives the relation between these quantities as
→A mass is hanging on a spring balance which is kept in a lift. The lift ascends. The spring balance will show in its reading
A monoatomic ideal gas, initially at temperature $T_1$, is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature. $T_2$ by releasing the piston suddenly. If $L_1$ and $L_2$ are the lengths of the gas column before and after expansion respectively, then $T_1 / T_2$ is given by
→