1
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

A particle of mass $m$ is moving around the origin with a constant force $F$ pulling it towards the origin. If Bohr model is used to describe its motion, the radius of the $n^{\text {th }}$ orbit and the particle's speed $v$ in the orbit depend on $n$ as

A
$r \propto n^{2 / 3} ; v \propto n^{1 / 3}$
B
$r \propto n^{4 / 3} ; v \propto n^{-1 / 3}$
C
$r \propto n^{1 / 3} ; v \propto n^{1 / 3}$
D
$r \propto n^{1 / 3} ; v \propto n^{2 / 3}$
2
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

In some appropriate units, time $(t)$ and position $(x)$ relation of a moving particle is given by $t=x^2+x$. The acceleration of the particle is

A
$+\frac{2}{(x+1)^3}$
B
$+\frac{2}{2 x+1}$
C
$-\frac{2}{(x+2)^3}$
D
$-\frac{2}{(2 x+1)^3}$
3
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

A model for quantized motion of an electron in a uniform magnetic field $B$ states that the flux passing through the orbit of the electron in $n(h l e)$ where $n$ is an integer, $h$ is Planck's constant and $e$ is the magnitude of electron's charge. According to the model, the magnetic moment of an electron in its lowest energy state will be ( $m$ is the mass of the electron)

A
$\frac{h e B}{\pi m}$
B
$\frac{h e B}{2 \pi m}$
C
$\frac{h e}{\pi m}$
D
$\frac{h e}{2 \pi m}$
4
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

A microscope has an objective of focal length 2 cm , eyepiece of focal length 4 cm and the tube length of 40 cm . If the distance of distinct vision of eye is 25 cm , the magnification in the microscope is

A
150
B
250
C
100
D
125
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