1 Particles MCQ

A sequence of radioactive decays starts with nuclide P and ends with an isotope of P. Which is a possible sequence for these decays?

• one alpha decay followed by four β⁻ decays

• one alpha decay followed by two β⁻ decays

• two alpha decays followed by two β⁻ decays

• two alpha decays followed by one β⁻ decay

The alpha particle, positron and proton have different charge-to-mass ratios. Which row shows the particles that have the greatest and the smallest value of this ratio?

• Greatest charge-to-mass ratio | Smallest charge-to-mass ratio

• A. positron | alpha particle

• B. positron | proton

• C. alpha particle | proton

• D. alpha particle | positron

Monochromatic radiation from light source P is incident on a metal surface and photoelectrons are emitted. When monochromatic radiation from light source Q is used, no photoelectrons are emitted. Which property of the radiation from P must be greater than that from Q?

• frequency

• intensity

• speed

• wavelength

The quark structure of the antiparticle of the K+ meson is

• u̅s

• u̅d

• u̅s̅

• d̅s

What is the de Broglie wavelength of a positron travelling at 5% of the speed of light?

• 2.7 × 10⁻¹⁶ m

• 2.7 × 10⁻¹⁴ m

• 4.9 × 10⁻¹³ m

• 4.9 × 10⁻¹¹ m

Which nuclear change results in the nucleus with the greatest specific charge?

• the alpha decay of a ²⁰⁹₈₂Po nucleus

• the beta-minus decay of a ²⁸₁₂Mg nucleus

• the beta-plus decay of a ³⁹₂₀Ca nucleus

• electron capture by a ¹⁰⁵₄₇Ag nucleus

In two separate experiments, electromagnetic radiation of variable frequency f is incident on the surfaces of plates made from metals X and Y. The work function of X is greater than the work function of Y. Which graph shows how the maximum kinetic energy E_k(max) of photoelectrons emitted from the surfaces of the plates varies with f?

• A

• B

• C

• D

Monochromatic light is incident on a metal surface in a vacuum and photoelectrons are emitted from the surface. The photoelectric current I is the rate of flow of charge from the surface. The maximum kinetic energy of the photoelectrons is E_k(max). E_k(max) and I are measured. The frequency of the light is then increased. There is no change to the rate at which energy is incident on the surface. What happens to E_k(max) and I when the frequency is increased?

• A. increases, decreases

• B. increases, no change

• C. no change, no change

• D. no change, decreases

An electron and a proton move with the same speed. What is de Broglie wavelength of electron / de Broglie wavelength of proton?

• 42

• 1800

Three energy levels for an atom are shown. Energy change E1 leads to the emission of a photon of wavelength λ1. Energy change E2 leads to the emission of a photon of wavelength λ2. What is λ1/λ2?

• 1/4

• 1/3

• 3

• 4