What is the frequency of the electron in the first orbit of hydrogen atom of orbital radius $0.5 \times 10^{-10} \mathrm{~m}$, if its orbital velocity in that orbit is $2.2 \times 10^6 \mathrm{~ms}^{-1}$.
$3.49 \times 10^{15} \mathrm{~Hz}$
$3.49 \times 10^{13} \mathrm{~Hz}$
$6.98 \times 10^{15} \mathrm{~Hz}$
$6.98 \times 10^{13} \mathrm{~Hz}$
An object is dropped from a certain point A at a height ' h ' from the ground. During it's journey straight downwards, the object passes points $B$ and $C$ such that the ratio of time taken $t_1$ to cover $A B$ and $t_2$ to cover $B C$ is $1:(\sqrt{2}-1)$. What is the ratio of distances $A B: B C$ ?
$1: 1$
$(\sqrt{2}-1): 1$
$1: \sqrt{2}$
$\sqrt{2}: 1$
In a single slit diffraction experiment, the diffraction pattern is observed on a screen placed at a distance of 2 m from the slit of 1 mm width. If the distance between the first dark fringe on either side of the central to right fringe is 2.2 mm . what is the wave length of the monochromatic light from a distance source, used in this experiment?
$3900^{\circ} \mathrm{A}$
$11000^{\circ} \mathrm{A}$
$1100^{\circ} \mathrm{A}$
$5500^{\circ} \mathrm{A}$
A wire, made of a certain material of length-l and area of cross section-a can withstand a maximum load $=\mathrm{W}$ without breaking. If, another wire of the same material and crosssectional area is used with double the original length, what will be the maximum load that the wire can withstand, without breaking?
Will be halved to 0.5 W
Will be doubled to 2 W
Remains the same $=\mathrm{W}$
Would be four times $=4 \mathrm{~W}$
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