Physics Past Questions and Answers

When an atom loses or gains a charge, it becomes

A An electron
B An ion
C A neutron
D A proton

Question 42:

4g of a radioactive material of half-life 10 days is spilled on a laboratory floor. How long would it take to disintegrate 3.5g of the material?

A 1\(\frac{1}{4}\) days
B 8\(\frac{1}{4}\) days
C 30 days
D 80 days

Question 43:

In a nuclear fusion process, four protons each of mass M_p were fused to produce a nucleus X of mass M_x. Which of the following equations is CORRECT?

A 4M_p > M_x
B 4M_p = M_x
C 4M_p < M_x
D M_p > M_x

Question 44:

Which of the following are True for \(\alpha\)-decay. i. mass number, decrease by four. ii. Atomic number decreases by two. iii. mass number does not change.

A I and ii only
B Ii and iii only
C I and iii only
D I, ii, and iii only

Question 45:

Which of the following phenomena is called photoelectric effect?

A High energy electrons impinge on a metalic anode which then emits photons
B A high energy photon emits photons as it slowed down
C A metal absorbs quanta of light and then emits electrons
D Two electrons are created from a quantum of light