Physics Past Questions and Answers

Borh's theory provides evidence for the

A Structure of the atom
B Positive charge of an electron
C Existence of energy level in the atom
D Positive charge on a proton

Question 757:

A nuclide \(^{202}_{84} Y\) emits in succession an \(\alpha-particle\) and a \(\beta-particle\). The atomic number of the resulting nuclide is

A 198
B 83
C 82
D 80

Question 758:

The half life of a radioactive substance is 14 days. If 48g of this substance is stored, after how many days will 1.5g of the original substance remain?

A 84 days
B 70 days
C 56 days
D 40 days

Question 759:

A material of mass 1.0 x 10^-2kg undergoes a fission process which decreases its mass by 0.02 percent. Calculate the amount of energy released in the process. (c = 3.0 x 10⁸ms^-1)

A 1.8 x 10²⁰J
B 1.8 x 10¹³J
C 1.8 x 10¹¹J
D 1.8 x 10¹⁰J

Question 760:

Absorption line spectra exhibited by atoms is a result of

A Change in the kinetic energy of a movimg atom
B Instability of the nucleons
C Excitation of an electron in the atom
D Transition of an electron from a higher to a lower energy level