1
JEE Main 2020 (Online) 6th September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Assuming the nitrogen molecule is moving with r.m.s. velocity at 400 K, the de-Broglie wavelength of nitrogen molecule is close to :
(Given : nitrogen molecule weight : 4.64 $$ \times $$ 10–26 kg,
Boltzman constant: 1.38 $$ \times $$ 10–23 J/K,
Planck constant : 6.63 $$ \times $$ 10–34 J.s)
A
0.44 $$\mathop A\limits^o $$
B
0.34 $$\mathop A\limits^o $$
C
0.20 $$\mathop A\limits^o $$
D
0.24 $$\mathop A\limits^o $$
2
JEE Main 2020 (Online) 6th September Morning Slot
MCQ (Single Correct Answer)
+4
-1
An electron, a doubly ionized helium ion (He++) and a proton are having the same kinetic energy. The relation between their respective de-Broglie wavelengths $$\lambda $$e, $$\lambda $$He++ and $$\lambda $$p is :
A
$$\lambda $$e > $$\lambda $$He++ > $$\lambda $$p
B
$$\lambda $$e < $$\lambda $$p < $$\lambda $$He++
C
$$\lambda $$e > $$\lambda $$p > $$\lambda $$He++
D
$$\lambda $$e < $$\lambda $$He++ = $$\lambda $$p
3
JEE Main 2020 (Online) 6th September Morning Slot
MCQ (Single Correct Answer)
+4
-1
You are given that Mass of $${}_3^7Li$$ = 7.0160u,
Mass of $${}_2^4He$$ = 4.0026u
and Mass of $${}_1^1H$$ = 1.0079u.
When 20 g of $${}_3^7Li$$ is converted into $${}_2^4He$$ by proton capture, the energy liberated, (in kWh), is :
[Mass of nucleon = 1 GeV/c2]
A
6.82 $$ \times $$ 105
B
4.5 $$ \times $$ 105
C
8 $$ \times $$ 106
D
1.33 $$ \times $$ 106
4
JEE Main 2020 (Online) 5th September Evening Slot
MCQ (Single Correct Answer)
+4
-1
The correct match between the entries in column I and column II are :

I II
Radiation Wavelength
(a) Microwave (i) 100 m
(b) Gamma rays (ii) 10–15 m
(c) A.M. radio waves (iii) 10–10 m
(d) X-rays (iv) 10–3 m
A
(a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)
B
(a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
C
(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
D
(a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)
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