# The energy associated with the fifth orbit of a hydrogen atom is : $1.$ $-2.18$ $×$ ${10}^{-18}$ $\mathrm{J}$$2.$ $-8.72$ $×$ ${10}^{-20}$ $\mathrm{J}$$3.$ $-3.88$ $×$ ${10}^{-21}$ $\mathrm{J}$$4.$ $-8.72$ $×$ ${10}^{-19}$ $\mathrm{J}$

Subtopic:  Hydrogen Spectra |
70%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The wave number for the longest wavelength transition in the Balmer series of atomic hydrogen would be -
1. $$1 . 1 . 52 \times \left(10\right)^{6} m^{- 1}$$
2. $$2 . 3 . 14 \times \left(10\right)^{6} \left(cm\right)^{- 1}$$
3. $$3 . 15 . 2 \times \left(10\right)^{6} m^{- 1}$$
4. $$4 . 1 . 52 \times \left(10\right)^{6} \left(cm\right)^{- 1}$$

Subtopic:  Hydrogen Spectra |
60%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The energy of an electron in an H - atom is given by $$E_n=(-2.18 \times10^{-18})/n^2~\mathrm J.$$ The shortest wavelength of light that can be used to remove an electron completely from $$n = 2$$ orbit will be:

 1 $$3647~\mathring{\mathrm A}$$ 2 $$5132~\mathring{\mathrm A}$$ 3 $$3017~\mathring{\mathrm A}$$ 4 None of these



Subtopic:  Hydrogen Spectra |
62%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The wavelength of an electron moving with a velocity of 2.05 × 107 m s-1  would be:

$$1 .$$ $$4 . 65$$ $$\times$$ $$\left(10\right)^{- 12}$$ $$m$$

$$2 .$$ $$3 . 55$$ $$\times$$ $$\left(10\right)^{-11}$$ $$m$$

$$3 .$$ $$2 . 34$$ $$\times$$ $$\left(10\right)^{11}$$ $$m$$

$$4 .$$ $$6 . 43$$ $$\times$$ $$\left(10\right)^{ -11}$$ $$m$$

Subtopic:  De Broglie Equation |
78%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The kinetic energy of an electron is $$3.0 \times 10^{-25}~ \mathrm J.$$ Its wave length would be:

 1 $$8.96 \times 10^{-7}~ \mathrm m$$ 2 $$4.37 \times 10^{-6}~ \mathrm m$$ 3 $$1.32 \times 10^{-7}~ \mathrm m$$ 4 $$2.89 \times 10^{-4}~ \mathrm m$$
Subtopic:  De Broglie Equation |
55%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The lowest value of n for 'g' orbitals is :
1. 4
2. 5
3. 3
4. 1

Subtopic:  Shell & Subshell |
71%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

An atom of an element contains 29 electrons and 35 neutrons. The number of protons in the element would be:

 1 29 2 35 3 6 4 64
Subtopic:  Number of Electron, Proton & Neutron |
83%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

If the diameter of a carbon atom is 0.15 nm, the number of carbon atoms that can be placed side by side in a straight line across the length of the scale of length 20 cm long will be:

 1 1.33 × 107 2 5.46 × 108 3 1.33 × 109 4 2.36 × 108



Subtopic:  Introduction of Atomic Structure |
70%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The charge on the oil drop is –1.282 × 10–18C. The number of electrons present in it would be :

1. 15

2. 8

3. 2

4. 6

Subtopic:  Number of Electron, Proton & Neutron |
81%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

An element with a mass number of 81 contains 31.7% more neutrons as compared to protons. The atomic symbol of the element would be

$1.$ ${}_{35}{}^{81}\mathrm{Br}$
$2.$ ${}_{36}{}^{81}\mathrm{Br}$
$3.$ ${}_{35}{}^{79}\mathrm{Br}$
$4.$ ${}_{36}{}^{79}\mathrm{Br}$

Subtopic:  Number of Electron, Proton & Neutron |
67%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch