WBJEE · Physics · Magnetic Effects of Current
A uniform magnetic field \(B\) exists in a region. An electron of charge \(q\) and mass \(m\) moving with velocity \(v\) enters the region in a direction perpendicular to the magnetic field. Considering Bohr angular momentum quantization, which of the following statement(s) is/are true?
- A The radius of \(\mathrm{n}^{\text {th }}\) orbit \(\mathrm{r}_{\mathrm{n}} \propto \sqrt{\mathrm{n}}\)
- B The maximum velocity of the electron is \(\frac{\sqrt{\mathrm{qB} \hbar}}{\mathrm{m}}\)
- C Energy of the \(n^{\text {th }}\) level \(E_n \propto n\)
- D Transition frequency \(\omega\) between two successive levels is independent of \(n\)
Answer & Solution
Correct Answer
(D) Transition frequency \(\omega\) between two successive levels is independent of \(n\)
Step-by-step Solution
Detailed explanation
Hint: \(r=\frac{m v}{q B}\) \(m v r=\frac{n h}{2 \pi}\) \(m v=\frac{n h}{2 \pi r}\) \(r=\frac{n h}{2 \pi r q B}\)…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- Four capacitors of equal capacitance have an equivalent capacitance \(\mathrm{C}_1\) when connected in series and an equivalent capacitance \(\mathrm{C}_2\) when connected in parallel. The ratio \(\frac{\mathrm{C}_1}{\mathrm{C}_2}\) is:WBJEE 2009 Easy
- If \(x=a t+b t^{2},\) where \(x\) is in metre \((\mathrm{m})\) and \(t\) is in hour \((\mathrm{h})\), then unit of \(b\) will beWBJEE 2016 Easy
-
A block of mass \(m\) slides with speed \(v\) on a frictionless table towards another stationary block of mass \(m\). A massless spring with spring constant \(\mathrm{k}\) is attached to the second block as shown in figure. The maximum distance the spring gets compress through isWBJEE 2021 Medium - The pressure \(p\), volume \(V\) and temperature \(T\) for a certain gas are related by \(p=\frac{A T-B T^{2}}{V}\) where \(A\) and \(B\) are constants. The work done by the gas when the temperature changes from \(T_{1}\) to \(T_{2}\) while the pressure remains constant, is given byWBJEE 2015 Hard
- Two blocks of \(2 \mathrm{~kg}\) and \(1 \mathrm{~kg}\) are in contact on a frictionless table. If a force of \(3 \mathrm{~N}\) is applied on \(2 \mathrm{~kg}\) block, then the force of contact between the two blocks will be :
WBJEE 2010 Medium -
Three blocks are pushed with a force \(\mathrm{F}\) across a frictionless table as shown in figure. Let \(\mathrm{N}_{1}\) be the contact force between the left two blocks and \(\mathrm{N}_{2}\) be the contact force between the right two blocks. ThenWBJEE 2021 Easy
More PYQs from WBJEE
- \(A B C\) is an isosceles triangle with an inscribed circle with centre \(O\). Let \(P\) be the midpoint of \(B C\). If \(A B=A C=15\) and \(B C=10\), then \(\mathrm{OP}\) equalsWBJEE 2023 Medium
- Given \(\overrightarrow{\mathrm{A}}=2 \hat{\mathrm{i}}+3 \hat{\mathrm{j}}\) and \(\overrightarrow{\mathrm{B}}=\hat{\mathrm{i}}+\hat{\mathrm{j}}\). The component of vector \(\overrightarrow{\mathrm{A}}\) along vector \(\overrightarrow{\mathrm{B}}\) isWBJEE 2011 Easy
- Which one of the following contains \(\mathrm{P}-\mathrm{O}-\mathrm{P}\) bond ?WBJEE 2010 Medium
- The maximum and minimum values of \(\cos ^{6} \theta+\sin ^{6} \theta\) are respectivelyWBJEE 2013 Easy
- If \(\left|\begin{array}{lll}x^k & x^{k+2} & x^{k+3} \\ y^k & y^{k+2} & y^{k+3} \\ z^k & z^{k+2} & z^{k+3}\end{array}\right|=(x-y)(y-z)(z-x)\left(\frac{1}{x}+\frac{1}{y}+\frac{1}{z}\right)\), thenWBJEE 2024 Easy
- Let \(A, B, C\) be three non-void subsets of set \(S\). Let \((A \cap C) \cup\left(B \cap C^{\prime}\right)=\phi\) where \(C^{\prime}\) denote the complement of set \(C\) in S. ThenWBJEE 2021 Easy