1
JEE Main 2022 (Online) 25th July Morning Shift
+4
-1

The momentum of an electron revolving in $$\mathrm{n}^{\text {th }}$$ orbit is given by :

(Symbols have their usual meanings)

A
$$\frac{\mathrm{nh}}{2 \pi \mathrm{r}}$$
B
$$\frac{n h}{2 r}$$
C
$$\frac{\mathrm{nh}}{2 \pi}$$
D
$$\frac{2 \pi r}{\mathrm{nh}}$$
2
JEE Main 2022 (Online) 30th June Morning Shift
+4
-1

A cyclotron is working at a frequency of 10 MHz. If the radius of its dees is 60 cm. The maximum kinetic energy of accelerated proton will be :

(Take : e = 1.6 $$\times$$ 10$$-$$19 C, mp = 1.67 $$\times$$ 10$$-$$27 kg)

A
7.4 MeV
B
14.86 MeV
C
7.4 GeV
D
704 GeV
3
JEE Main 2022 (Online) 30th June Morning Shift
+4
-1

A hydrogen atom in ground state absorbs 12.09 eV of energy. The orbital angular momentum of the electron is increased by :

A
1.05 $$\times$$ 10$$-$$34 Js
B
2.11 $$\times$$ 10$$-$$34 Js
C
3.16 $$\times$$ 10$$-$$34 Js
D
4.22 $$\times$$ 10$$-$$34 Js
4
JEE Main 2022 (Online) 29th June Evening Shift
+4
-1

In the following nuclear reaction,

$$D\buildrel \alpha \over \longrightarrow {D_1}\buildrel {{\beta ^ - }} \over \longrightarrow {D_2}\buildrel \alpha \over \longrightarrow {D_3}\buildrel \gamma \over \longrightarrow {D_4}$$

Mass number of D is 182 and atomic number is 74. Mass number and atomic number of D4 respectively will be _________.

A
174 and 71
B
174 and 69
C
172 and 69
D
172 and 71
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