HARD
JEE Main
IMPORTANT
Earn 100

Which of the following equations describe(s) particle-like behaviour? Which equation describe(s) wave-like behaviour? Do any equations involve both types of behaviour?

a C=νλ

b E=mc2

c r=n2a0Z

d E=

e λ=h

Important Questions on Atomic Structure and Radioactivity

HARD
JEE Main
IMPORTANT

The quantum numbers listed below are for four different electrons in the same atom. Arrange them in the order of increasing energy. Indicate whether any of the two orbitals have the same energy.

a n=4, l=0, ml=0 and s=+12

b n=3, l=2, ml=+1 and s=+12

c n=3, l=2, ml=-2 and s=-12

d n=3, l=1, ml=+1 and s=-12

MEDIUM
JEE Main
IMPORTANT
When compounds of barium are heated in a flame, a green light of wave length 554 nm is emitted. How much energy in joule is lost when one mole of barium atoms each emit one photon of this wave length?
HARD
JEE Main
IMPORTANT

What is the energy evolved in J when 1 mole of He-4 nuclei is produced from protons and neutrons? If 4.9×10x liters of C2H6(g) are needed at 25°C and 725 mm Hg to evolve the same quantity of energy when C2H6 is burnt in O2? Find the value of x.

(Mass of Neutron =1.008867 amu, Mass of proton =1.00728 amu, Mass of He=4.0015 amu and HcombC2H6=-1427.81 kJ/mol)

MEDIUM
JEE Main
IMPORTANT
A 1.0 mg sample of Tc-99 has an activity of 1.7×10-5 curie, decaying by β-emission. Calculate the decay constant.
MEDIUM
JEE Main
IMPORTANT
Tritium, H13 is a radioactive nucleus of hydrogen. It is used in luminous watch dials. Tritium decays by β-emission with t1/2=12.3 years. What is the activity in curie of a sample containing 2·5 μg of tritium? The atomic mass of tritium is 3·02 amu.
MEDIUM
JEE Main
IMPORTANT

Predict the type of radioactive decay process that is likely for each of the following nuclides.

(a) U92228  (b) B58  (c) Cu2968

MEDIUM
JEE Main
IMPORTANT
If 28.0% of a sample of Ag-112 decays in 1.52 h, what is the half-life of this isotope?
MEDIUM
JEE Main
IMPORTANT
Th90232 disintegrates to Pbyx by emitting six α- and four β-particles. Find x and y.