1
JEE Main 2023 (Online) 13th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The energy of an electron in the first Bohr orbit of hydrogen atom is $$-2.18 \times 10^{-18} \mathrm{~J}$$. Its energy in the third Bohr orbit is ____________.

A
One third of this value
B
Three times of this value
C
$$\frac{1}{9}$$ th of this value
D
$$\frac{1}{27}$$ of this value
2
JEE Main 2023 (Online) 11th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : In the photoelectric effect, the electrons are ejected from the metal surface as soon as the beam of light of frequency greater than threshold frequency strikes the surface.

Reason R : When the photon of any energy strikes an electron in the atom, transfer of energy from the photon to the electron takes place.

In the light of the above statements, choose the most appropriate answer from the options given below :

A
Both A and R are correct and R is the correct explanation of A
B
A is not correct but R is correct
C
A is correct but R is not correct
D
Both A and R are correct but R is NOT the correct explanation of A
3
JEE Main 2023 (Online) 8th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Henry Moseley studied characteristic X-ray spectra of elements. The graph which represents his observation correctly is

Given $$v=$$ frequency of $$\mathrm{X}$$-ray emitted

Z = atomic number

A
JEE Main 2023 (Online) 8th April Evening Shift Chemistry - Structure of Atom Question 29 English Option 1
B
JEE Main 2023 (Online) 8th April Evening Shift Chemistry - Structure of Atom Question 29 English Option 2
C
JEE Main 2023 (Online) 8th April Evening Shift Chemistry - Structure of Atom Question 29 English Option 3
D
JEE Main 2023 (Online) 8th April Evening Shift Chemistry - Structure of Atom Question 29 English Option 4
4
JEE Main 2023 (Online) 6th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

If the radius of the first orbit of hydrogen atom is $$\alpha_{0}$$, then de Broglie's wavelength of electron in $$3^{\text {rd }}$$ orbit is :

A
$$\frac{\pi \alpha^{3}}{6}$$
B
$$3\pi\alpha_0$$
C
$$6\pi\alpha_0$$
D
$$\frac{\pi \alpha^{3}}{3}$$
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