1
JEE Main 2022 (Online) 26th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

If the radius of the 3rd Bohr's orbit of hydrogen atom is r3 and the radius of 4th Bohr's orbit is r4. Then :

A
$${r_4} = {9 \over {16}}{r_3}$$
B
$${r_4} = {16 \over {9}}{r_3}$$
C
$${r_4} = {3 \over {4}}{r_3}$$
D
$${r_4} = {4 \over {3}}{r_3}$$
2
JEE Main 2022 (Online) 25th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is :

[Given : The threshold frequency of platinum is 1.3 $$\times$$ 1015 s$$-$$1 and h = 6.6 $$\times$$ 10$$-$$34 J s.]

A
3.21 $$\times$$ 10$$-$$14 J
B
6.24 $$\times$$ 10$$-$$16 J
C
8.58 $$\times$$ 10$$-$$19 J
D
9.76 $$\times$$ 10$$-$$20 J
3
JEE Main 2022 (Online) 25th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The pair, in which ions are isoelectronic with AI3+ is :

A
Br$$-$$ and Be2+
B
Cl$$-$$ and Li+
C
S2$$-$$ and K+
D
O2$$-$$ and Mg2+
4
JEE Main 2022 (Online) 24th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The energy of one mole of photons of radiation of wavelength 300 nm is

(Given : h = 6.63 $$\times$$ 10$$-$$34 J s, NA = 6.02 $$\times$$ 1023 mol$$-$$1, c = 3 $$\times$$ 108 m s$$-$$1)

A
235 kJ mol$$-$$1
B
325 kJ mol$$-$$1
C
399 kJ mol$$-$$1
D
435 kJ mol$$-$$1
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