1
MHT CET 2022 11th August Evening Shift
+1
-0

Using Bohr's model, the orbital period of electron in hydrogen atom in the $$\mathrm{n}^{\text {th }}$$ orbit is $$\left(\varepsilon_0=\right.$$ permittivity of vacuum, $$\mathrm{h}=$$ Planck's constant, $$\mathrm{m}=$$ mass of electron, $$\mathrm{e}=$$ electronic charge)

A
$$\frac{4 \varepsilon_0 \mathrm{nh}^3}{\mathrm{me}^2}$$
B
$$\frac{4 \varepsilon_0 \mathrm{n}^2 \mathrm{~h}^2}{\mathrm{me}^2}$$
C
$$\frac{4 \varepsilon_0^2 n^3 h^3}{m e^4}$$
D
$$\frac{4 \varepsilon_0^2 \mathrm{n}^2 \mathrm{~h}^3}{m \mathrm{e}^3}$$
2
MHT CET 2022 11th August Evening Shift
+1
-0

The wave number of the last line of the Balmer series in hydrogen spectrum will be

(Rydberg's constant $$=10^7 \mathrm{~m}^{-1}$$ )

A
$$250 \mathrm{~m}^{-1}$$
B
$$2.5 \times 10^6 \mathrm{~m}^{-1}$$
C
$$0.25 \times 10^9 \mathrm{~m}^{-1}$$
D
$$2.5 \times 10^5 \mathrm{~m}^{-1}$$
3
MHT CET 2021 24th September Evening Shift
+1
-0

The half life of a radioactive substance is 30 minute. The time taken between 40% decay and 85% decay of the same radioactive substance is

A
15 minute
B
90 minute
C
60 minute
D
30 minute
4
MHT CET 2021 24th September Evening Shift
+1
-0

The ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) second to first energy level and (ii) highest energy level to second energy level is

A
$$6:1$$
B
$$3: 1$$
C
$$12: 1$$
D
$$8: 1$$
EXAM MAP
Medical
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