MCQ
The De-broglie $\lambda$ of electron in the $2^{st}$ Bohr orbit is
- A$4\pi r_1$
- ✓$\pi r_1$
- C$2\pi r_1$
- D$6\pi r_1$
✓
Answer
Correct option: B.
$\pi r_1$
b
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
The total number of stereoisomers that can exist for $M$ is
→$Image$
Which $L-$ sugar on oxidation gives an optically active dibasic acid ($2\,COOH$ groups) ?
→Starting from propanoic acid, the following reactions were carried out
→${\text{Propanoic acid }}\xrightarrow{{SOC{l_2}}}X\xrightarrow{{N{H_3}}}Y\xrightarrow{{B{r_2} + KOH}}Z$
What is the compound $Z$
The mechanism of the reaction $2NO_2 + F_2 \to 2NO_2F$ is
→$(i)$ $N{O_2}\xrightarrow{{slow}}NO + O$
$(ii)$ ${F_2} + O + NO\xrightarrow{{Fast}}N{O_2}F + F$
$(iii)$ $F + N{O_2}\xrightarrow{{Fast}}N{O_2}F$
Select the correct one
The number of molecules in $16\, g$ of methane is
→The molar heat capacity for an ideal gas at constant pressure is $20.785\,J\,K ^{-1}\,mol ^{-1}$. The change in internal energy is $5000\,J$ upon heating it from $300\,K$ to $500\,K$. The number of moles of the gas at constant volume is [Nearest integer] (Given: $R =8.314\,J\,K ^{-1}\,mol ^{-1}$)
→Oxalic acid on being heated upto ${90\,^o}C$ with conc. ${H_2}S{O_4}$ forms
→The atomic number of the element from the following with lowest $1^{\text {st }}$ ionisation enthalpy is :
→Colour of $CrO_4^{^{2 - }}(aq.)$ is not changed by
→Among $H_2O, H_2S, H_2Se$ and $H_2Te$. The one with the highest boiling point is
→