1

### IIT-JEE 2002 Screening

If the nitrogen atom has electronic configuration 1s7, it would have energy lower than that of the normal ground state configuration 1s22s22p3, because the electrons would be closer to the nucleus. Yet 1s7 is not observed because it violates
A
Heisenberg uncertainty principle
B
Hund's rule
C
Pauli exclusion principle
D
Bohr postulate of stationary orbits
2

### IIT-JEE 2002 Screening

Rutherford's experiment, which established the nuclear model of the atom, used a beam of
A
$\beta-particles$, which impinged on a metal foil and got absorbed
B
$\gamma-particles$, which impinged on a metal foil and ejected electrons
C
helium atoms, which impinged on a metal foil and got scattered
D
helium nuclei, which impinged on a metal foil and got scattered
3

### IIT-JEE 2001 Screening

The quantum numbers +1/2 and -1/2 for the electron spin represent
A
rotation of the electron in clockwise and anticlockwise direction respectively
B
rotation of the electron in anticlockwise and clockwise direction respectively
C
magnetic moment of the electron pointing up and down respectively
D
two quantum mechanical spin states which have no classical analogue
4

### IIT-JEE 2001 Screening

The wavelength associated with a golf ball weighing 200 g and moving at speed of 5 m/h is of the order
A
10-10 m
B
10-20 m
C
10-30 m
D
10-40 m