1
WB JEE 2019
MCQ (Single Correct Answer)
+1
-0.25
Change Language
To which of the following the angular velocity of the electron in the n-th Bohr orbit is proportional?
A
$${n^2}$$
B
$${1 \over {{n^2}}}$$
C
$${1 \over {{n^{3/2}}}}$$
D
$${1 \over {{n^3}}}$$
2
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
How the linear velocity v of an electron in the Bohr orbit is related to its quantum number n?
A
$$v \propto {1 \over n}$$
B
$$v \propto {1 \over {{n^2}}}$$
C
$$v \propto {1 \over {\sqrt n }}$$
D
$$v \propto n$$
3
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
If the half-life of a radioactive nucleus is 3 days, nearly what fraction of the initial number of nuclei will decay on the third day? (Given, $$\root 3 \of {0.25} \approx 0.63$$)
A
0.63
B
0.5
C
0.37
D
0.13
4
WB JEE 2018
MCQ (Single Correct Answer)
+1
-0.25
Change Language
An electron accelerated through a potential of 10000 V from rest has a de-Broglie wave length $$\lambda$$. What should be the accelerating potential, so that the wavelength is doubled?
A
20000 V
B
40000 V
C
5000 V
D
2500 V
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