Verified past-paper data not yet uploaded
No verified paper has been uploaded for AJKPSC-PMS Paper Physics 2022 MCQs yet.
The MCQs below are drawn from the Physics subject category.
Showing 2261–2270
of 15583 MCQs
Page 227 / 1559
2261
The convincing evidence of the wave nature of electrons was provided by
A. Davison and Germer
B. Rayleigh
C. Balmer
D. Lummer
Discuss
Save
Correct Option
Explanation
Davisson and Germer's electron diffraction experiments provided convincing evidence for the wave nature of electrons.
2262
Referring to the above figure, the binding energy per nucleon:
A. First increases, reaches the peak and then decreases
B. Goes on increasing
C. Goes on decreasing
D. First increases, becomes nearly constant and then decreases
Discuss
Save
Correct Option
Explanation
Empirical binding energy curve shows it rises to a peak (around iron) and then decreases for heavier nuclei.
2263
Mass of meson is:
A. Equal to neutron
B. Less than proton
C. Greater than proton
D. Equal to proton
Discuss
Save
Correct Option
Explanation
Mesons are typically lighter than protons (they are intermediate-mass hadrons), so their mass is less than that of a proton.
2264
To allow the entry of a- or B-particles, one end of the G.M. tube has a:
A. Airy window
B. Thin glass window
C. Wooden window
D. Thin mica window
Discuss
Save
Correct Option
Explanation
A thin mica window allows alpha and beta particles to enter the detector with minimal attenuation while maintaining the gas seal.
2265
For an electron or positron, the rest-mass energy is equal to
A. 1.51 MeV
B. 0.21 MeV
C. 0.51 MeV
D. 1.21 MeV
Discuss
Save
Correct Option
Explanation
Block-level answer hint indicates option A; this field reflects the provided block answer hint.
2266
If atomic mass of iron is 55.9, then the mass of an iron atom on the average be:
A. 9.3 × 10^-28 kg/atom
B. 9.3 × 10^-26 kg/atom
C. 9.3 × 10^-25 kg/atom
D. 9.3 × 10^-2 kg/atom
Discuss
Save
Correct Option
Explanation
Atomic mass 55.9 u × 1.6605×10^-27 kg/u ≈ 9.3×10^-26 kg per atom, matching option C.
2267
Which of the following statements are true regarding radioactivity? (I) All radioactive elements decay exponentially with time (II) Half life time of a radioactive element is time required for one half of the radioactive atoms to disintegrate (III) Age of earth can be determined with the help of radioactive dating (IV) Half-life time of a radioactive element is fifty percent of its average life period. Select the correct answer using the codes given below.
A. I, II and III
B. I, II and IV
C. I and II
D. II and III
Discuss
Save
Correct Option
Explanation
Statements I, II and III are correct; IV is false because half-life = 0.693×mean life, not 0.5×mean life.
2268
Velocity of electron moving in first orbit of hydrogen is
A. 2.19 x 10^? m/sec
B. 2.19 x 10^6 m/sec
C. 2.2 x 10^8 m/sec
D. 2.18 x 10^7 m/sec
Discuss
Save
Correct Option
Explanation
The OCR answer key indicates option D (2.19 × 10^6 m/s) as the velocity for the electron in the first Bohr orbit.
2269
Radio-isotopes used for the treatment of the cancer of thyroid gland is:
A. I-131
B. Co-60
C. Sr-90
D. P-32
Discuss
Save
Correct Option
Explanation
Iodine-131 is the standard radioisotope used to treat thyroid cancer and hyperthyroidism because thyroid tissue selectively absorbs iodine.
2270
The ratio of the rate of decay of a parent atom to the number of radioactive nuclei present at that time is equal to:
A. Decay constant of radioactive element
B. Half-life of radioactive element
C. Mean life
D. Activity of radioactive element
Discuss
Save
Correct Option
Explanation
Decay constant λ is defined as decay rate divided by the number of nuclei (rate/N).
