1
MCQ (Single Correct Answer)

AIPMT 2007

Consider the following sets of quantum numbers :

n l m s
(i) 3 0 0 +1/2
(ii) 2 2 1 +1/2
(iii) 4 3 -2 -1/2
(iv) 1 0 -1 -1/2
(v) 3 2 3 +1/2


Which of the following sets of quantum number is not possible ?
A
(i), (ii), (iii) and (iv)
B
(ii), (iv) and (v)
C
(i) and (iii)
D
(ii), (iii) and (iv)

Explanation

(i) represents an electron in 3s orbital

(ii) is not possible as value of m varies from 0, 1, .... ($$n$$ -1)

(iii) represents an electron in 4f orbital

(iv) is not possible as value of m varies from -$$l$$ ... +$$l$$

(v) is not possible as value of m varies from -$$l$$ ... +$$l$$, it can never be grater than $$l$$
2
MCQ (Single Correct Answer)

AIPMT 2006

Given : The mass of electron is 9.11 $$ \times $$ 10$$-$$31 kg, Planck constant is 6.626 $$ \times $$ 10$$-$$34 J s, the uncertainty involved in the measurement of velocity within a distance of 0.1 $$\mathop A\limits^ \circ $$ is
A
5.79 $$ \times $$ 105 m s$$-$$1
B
5.79 $$ \times $$ 106 m s$$-$$1
C
5.79 $$ \times $$ 107 m s$$-$$1
D
5.79 $$ \times $$ 108 m s$$-$$1

Explanation

$$\Delta x.m\Delta v = h/4\pi $$

0.1 $$ \times $$ 10-10 $$ \times $$ 9.11 $$ \times $$ 10-31 $$ \times $$ $$\Delta v$$ = $${{6.626 \times {{10}^{ - 34}}} \over {4 \times 3.143}}$$

$$ \therefore $$ $$\Delta v$$ = $${{6.626 \times {{10}^{ - 34}}} \over {4 \times 3.143 \times 0.1 \times {{10}^{ - 10}} \times 9.11 \times {{10}^{ - 31}}}}$$

= 5.79 $$ \times $$ 106 m s-1
3
MCQ (Single Correct Answer)

AIPMT 2006

The orientation of an atomic orbital is governed by
A
principal quantum number
B
azimuthal quantum number
C
spin quantum number
D
magnetic quantum number.

Explanation

Magnetic quantum number describes the orientation.
4
MCQ (Single Correct Answer)

AIPMT 2005

The energy of second Bohr orbit of the hydrogen atom is $$-$$328 kJ mol$$-$$1; hence the energy of fourth Bohr orbit would be
A
$$-$$ 41 kJ mol$$-$$1
B
$$-$$82 kJ mol$$-$$1
C
$$-$$164 kJ mol$$-$$1
D
$$-$$1312 kJ mol$$-$$1

Explanation

En = -K$${\left( {{Z \over n}} \right)^2}$$

Z = 1; n = 2

E2 = $${ {{-K \times 1 \over 4}}}$$$$ \Rightarrow $$ E2 = -328 kJ mol-1;

K = 4 $$ \times $$ 328

E4 = $${ {{-K \times 1 \over 16}}}$$ $$ \Rightarrow $$ E4 = -4 $$ \times $$ 328 $${ {{ 1 \over 16}}}$$

= -82 kJ mol-1

EXAM MAP

Joint Entrance Examination

JEE Advanced JEE Main

Medical

NEET

Graduate Aptitude Test in Engineering

GATE CSE GATE ECE GATE ME GATE PI GATE EE GATE CE GATE IN