1

### IIT-JEE 1988

The triad of nuclei that is isotonic is
A
${}_6^{14}C$, ${}_7^{15}N$, ${}_9^{17}C$
B
${}_6^{12}C$, ${}_7^{14}N$, ${}_9^{19}C$
C
${}_6^{14}C$, ${}_7^{14}N$, ${}_9^{17}C$
D
${}_6^{14}C$, ${}_7^{14}N$, ${}_9^{19}C$
2

### IIT-JEE 1986

The ratio of the energy of a photon of 2000Å wavelength to that 4000Å radiation is
A
1/4
B
4
C
1/2
D
2
3

### IIT-JEE 1986

Which one of the following sets of quantum numbers represents an impossible arrangement?
A
n = 3, l = 2, ml = -2, ms = 1/2
B
n = 4, l = 0, ml = 0, ms = 1/2
C
n = 3, l = 2, ml = -3, ms = 1/2
D
n = 5, l = 3, ml = 0, ms = -1/2
4

### IIT-JEE 1986

Rutherford's alpha particle scattering experiment eventually led to the conclusion that:
A
mass and energy are related
B
electrons occupy space around the nucleus
C
neutrons are buried deep in the nucleus
D
the point of impact with matter can be precisely determined