JEE Mains · Physics · STD 12 - 12. atoms
The momentum of an electron revolving in \(n ^{\text {th }}\) orbit is given by: (Symbols have their usual meanings)
- A \(\frac{ nh }{2 \pi r }\)
- B \(\frac{ nh }{2 r }\)
- C \(\frac{ nh }{2 \pi}\)
- D \(\frac{2 \pi r }{ nh }\)
Answer & Solution
Correct Answer
(A) \(\frac{ nh }{2 \pi r }\)
Step-by-step Solution
Detailed explanation
Angular momentum \(mrV =\frac{ nh }{2 \pi}\) So momentum \(mv =\frac{ nh }{2 \pi r }\)
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
- A pole is vertically submerged in swimming pool, such that it gives a length of shadow \(2.15 \,m\) within water when sunlight is incident at an angle of \(30^{\circ}\) with the surface of water. If swimming pool is filled to a height of \(1.5\,m\), then the height of the pole above the water surface in centimetres is \(\left(\eta_W=4 / 3\right)........\)JEE Mains 2023 Hard
- The escape velocity from a spherical planet A is 10 km/s. The escape velocity from another planet B whose density and radius are 10% of those of planet A, is __________ m/s.JEE Mains 2026 Medium
- The value of numerical aperature of the objective lens of a microscope is \(1.25\). If light of wavelength \(5000\,\mathop A\limits^o \) is used, the minimum separation between two points, to be seen as distinct, will be....\(\mu m\)JEE Mains 2019 Medium
- A boy thrown a ball into air at \(45^{\circ}\) from the horizontal to land it on a roof of a building of height H . If the ball attains maximum height in 2 s and lands on the building in 3 s after launch, then value of H is _________ m .
\(\left( g =10 m / s ^2\right)\)JEE Mains 2026 Medium - A 1 m long metal rod AB completes the circuit as shown in figure. The area of circuit is perpendicular to the magnetic field of 0.10 T . If the resistance of the total circuit is \(2 \Omega\) then the force needed to move the rod towards right with constant speed (v) of \(1.5 m / s\) is _________ N.
JEE Mains 2026 Hard - The speed verses time graph for a particle is shown in the figure. The distance travelled (in \(m\) ) by the particle during the time interval \(t=0\) to \(t=5\, s\) will be
JEE Mains 2020 Easy
More PYQs from JEE Mains
- The magnetic field \(B\) crossing normally a square metallic plate of area \(4\,m ^2\) is changing with time as shown in figure. The magnitude of induced \(emf\) in the plate during \(t=2\,s\) to \(t=4\,s\), is \(..........\,mV\)
JEE Mains 2023 Hard - If the distance between the plane, \(23 \mathrm{x}-10 \mathrm{y}-2 \mathrm{z}+48=0\) and the plane containing the lines \(\frac{x+1}{2}=\frac{y-3}{4}=\frac{z+1}{3}\) and \(\frac{x+3}{2}=\frac{y+2}{6}=\frac{z-1}{\lambda}(\lambda \in R)\) is equal to \(\frac{\mathrm{k}}{\sqrt{633}},\) then \(\mathrm{k}\) is equal toJEE Mains 2020 Hard
- A large number of water drops, each of radius \(r\), combine to have a drop of radius \(R\). If the surface tension is \(T\) and mechanical equivalent of heat is \(J ,\) the rise in heat energy per unit volume will beJEE Mains 2021 Hard
- As shown in the figure an inductor of inductance \(200\, mH\) is connected to an \(AC\) source of emf \(220 \,V\) and frequency \(50 \,Hz\). The instantaneous voltage of the source is \(0\, V\) when the peak value of current is \(\frac{\sqrt{a}}{\pi} A\). The value of a is..........
JEE Mains 2022 Medium - A pendulum is executing simple harmonic motion and its maximum kinetic energy is \(K_1\). If the length of the pendulum is doubled and it performs simple harmonic motion with the same amplitude as in the first case, its maximum kinetic energy is \(K_2\) thenJEE Mains 2019 Medium
- The distance of the point having position vector \( - \,\hat i\, + \,2\hat j\, + 6\hat k\) from the straight line passing through the point \((2, 3, -4)\) and parallel to the vector \(6\,\hat i\, + 3\hat j\, - 4\hat k\) isJEE Mains 2019 Easy