1
JEE Main 2021 (Online) 24th February Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
An X-ray tube is operated at 1.24 million volt. The shortest wavelength of the produced photon will be :
A
10$$-$$2 nm
B
10$$-$$1 nm
C
10$$-$$3 nm
D
10$$-$$4 nm
2
JEE Main 2021 (Online) 24th February Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Match List - I with List - II.

List I List II
(a) Source of microwave frequency (i) Radioactive decay of nucleus
(b) Source of infrared frequency (ii) Magnetron
(c) Source of Gamma Rays (iii) Inner shell electrons
(d) Source of X-rays (iv) Vibration of atoms and molecules
(v) LASER
(vi) RC circuit


Choose the correct answer from the options given below :
A
(a)-(vi), (b)-(v), (c)-(i), (d)-(iv)
B
(a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)
C
(a)-(ii), (b)-(iv), (c)-(vi), (d)-(iii)
D
(a)-(vi), (b)-(iv), (c)-(i), (d)-(v)
3
JEE Main 2021 (Online) 24th February Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
According to Bohr atom model, in which of the following transitions will the frequency be maximum?
A
n = 2 to n = 1
B
n = 3 to n = 2
C
n = 4 to n = 3
D
n = 5 to n = 4
4
JEE Main 2021 (Online) 24th February Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Given below are two statements :

Statement I : Two photons having equal linear momenta have equal wavelengths.

Statement II : If the wavelength of photon is decreased, then the momentum and energy of a photon will also decrease.

In the light of the above statements, choose the correct answer from the options given below.
A
Statement I is false but Statement II is true
B
Both Statement I and Statement II are false
C
Both Statement I and Statement II are true
D
Statement I is true but Statement II is false
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