Agniveer Army Technical Modern Physics Questions

An alpha particle (He-4 nucleus) has a mass defect of 0.0305 u. What is its binding energy? (1 u = 931 MeV/c²)

In a semiconductor material, the forbidden energy gap (band gap) is defined as:

The ionization energy of a hydrogen atom is the energy required to remove the electron from the first orbit. This value is:

The radius of a nucleus is given by R = R₀A^(1/3), where R₀ ≈ 1.2 fm. If nucleus A has mass number 8 and nucleus B has mass number 27, what is the ratio of their radii R_A : R_B?

A semiconductor has an intrinsic carrier concentration of ni = 1.5 × 10¹⁰ cm⁻³ at 300 K. If the semiconductor is doped with donor impurities to make it n-type with carrier concentration n = 1.5 × 10¹⁵ cm⁻³, what is the hole concentration p in this n-type semiconductor?

A p-n junction diode is forward biased with an applied voltage of 0.6 V. If the thermal voltage kT/e at room temperature is 0.026 V, what is the approximate diode current relative to its reverse saturation current I₀ using the ideal diode equation I = I₀(e^(eV/kT) − 1)?

The energy of an electron in the second orbit (n=2) of a hydrogen atom is -3.4 eV. What is the energy of the electron in the first orbit (n=1)?

Which of the following statements about the ground state of a hydrogen atom is correct?

The binding energy per nucleon is maximum for nuclei with mass number around:

A nucleus undergoes beta-minus decay. What happens to the atomic number (Z) and mass number (A)?

An electron accelerated through a potential difference of 50 V has a de Broglie wavelength of 1.73 × 10⁻¹⁰ m. Which statement correctly describes the dual nature illustrated here?

In nuclear fission, a heavy nucleus splits into two lighter nuclei. Which statement is correct?

The de Broglie wavelength of a moving particle is given by λ = h/p. If an electron (mass = 9.1 × 10⁻³¹ kg) moves with velocity 2 × 10⁶ m/s, calculate its de Broglie wavelength. (h = 6.63 × 10⁻³⁴ J·s)

Which of the following statements correctly describes the energy band structure of a semiconductor at 0 K?

In the photoelectric effect, Einstein's photon theory explains that light consists of discrete energy packets. Which phenomenon directly proves the particle nature of radiation?

According to Bohr's model of the hydrogen atom, the radius of the first orbit (Bohr radius) is approximately:

A light wave of wavelength 500 nm is diffracted through a slit, and simultaneously, individual photons from this light eject electrons from a photoelectric surface. Which aspect of dual nature is demonstrated respectively?

An electron transitions from the third orbit (n=3) to the second orbit (n=2) in a hydrogen atom. The energy of the emitted photon is:

A photon of frequency 6 × 10¹⁵ Hz is incident on a metal surface. If the Planck's constant h = 6.63 × 10⁻³⁴ J·s, calculate the energy of the photon.

A silicon semiconductor is doped with acceptor impurities to create a p-type semiconductor. Which of the following is the primary charge carrier in this p-type material?

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