The electron in a hydrogen atom makes a transition 
, where 
and 
are the principal quantum numbers of the two states. Assume the Bohr model to be valid. The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 and n2 are
|
(a) |
(b) |
(c) |
(d) |
(d) 
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
The temperature at which thermal electric power of a thermo couple becomes zero is called
|
(a) Inversion temperature |
(b) Neutral temperature |
|
(c) Junction temperature |
(d) Null temperature |
$\frac{1}{4}\text{mgR}$
$\frac{1}{2}\text{mgR}$
$\text{mgR}$
$2\text{mgR}$
Two cells of equal e.m.f. and of internal resistances 
and 
are connected in series. On connecting this combination to an external resistance R, it is observed that the potential difference across the first cell becomes zero. The value of R will be
|
(a) |
(b) |
(c) |
(d) |
$\vec{\text{r}}.\vec{\text{F}}=0$ and $\vec{\text{F}}.\vec{\tau}=0$
$\vec{\text{r}}.\vec{\tau}=0$ but $\vec{\text{F}}.\vec{\tau}\neq0$
$\vec{\text{r}}.\vec{\tau}\neq0$ but $\vec{\text{F}}.\vec{\tau}=0$
$\vec{\text{r}}.\vec{\tau}\neq0$ and $\vec{\text{F}}.\vec{\tau}\neq0$
An electron and a proton enter a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true
|
(a) Trajectory of electron is less curved |
(b) Trajectory of proton is less curved |
|
(c) Both trajectories are equally curved |
(d) Both move on straight-line path |
