General Studies [3i Infotech Placement]: Sample Questions 1 - 2 of 2

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Question 1

General Studies

Question

MCQ▾

An electron emits energy

Choices

Choice (4)

a.

Electrons are attracted towards the nucleus

b.

When it jumps from one energy level to another

c.

Because it՚s in orbit

d.

The electrostatic force is insufficient to hold the electrons in orbits

Answer

b.

Explanation

Understanding of Abstraction and Emission
  • An electron emits energy when it jumps from one energy level to another.
  • Radiation interacts with matter in terms of “packets” of energy called “quanta” or “photons” .
  • Where plank՚s constant

  • Energetically excited atoms only emit discrete energies corresponding to the atom՚s electronic energy levels.

Question 2

General Studies

Question

MCQ▾

The maximum KE of the photoelectron emitted from surface is dependent on

Choices

Choice (4)

a.

The angle of incidence of radiation of the surface

b.

The potential of the collector electrode

c.

The intensity of incident radiation

d.

The frequency of incident radiation

Answer

d.

Explanation

Equation of Kinetic Energy
  • If we change the intensity of the incident beam keeping the frequency of light same, we only change the number of photons.
  • The change in that number cannot affect the kinetic energy of the emitted electrons.
  • The emission of electrons occurs due to a one electron one photon collision. If one photon of insufficient energy collides with an electron and then another one does, the energy of the electron does not become twice that of the incident photon- assuming that the energy gained from the first collision dissipates fast.
  • The maximum KE of the photoelectron emitted from a surface is dependent on the frequency of incident radiation - which changes the energy of each photon.

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