MCQs – Radius, diffraction, inverse square law (set 2)

In the Rutherford scattering experiment, α-particles were fired at a thin gold foil. A small proportion of the α-particles were deflected through large angles. Which statement gives the correct conclusion that could be drawn directly from these results?

• The atom is made up of electrons, protons and neutrons.

• The nucleus is at the centre of the atom.

• The nucleus is made up of protons and neutrons.

• The atom contains a very small, charged nucleus.

Alpha, beta and gamma radiations: 1. are absorbed to different extents in solids, 2. behave different in an electric field, 3. behave different in a magnetic field. The diagrams illustrate these behaviours. Which three labels on these diagram refer to the same kind of radiation?

• L, P, X

• L, P, Z

• M, P, Z

• N, Q, X

Which graph illustrates the relationship between irradiance (detected intensity) from a point source and distance from the source?

• 
• 
• 

Which one of the following statements does not help to explain why electrons can be used to probe the nuclei of atoms?

• Electrons are negatively charged.

• Electrons can have wavelengths similar in size to nuclear diameters.

• Electrons can be accelerated to high energies.

• Electrons can exhibit diffraction effects.

A student conducts an experiment using an α-particles source. When considering safety precautions, what can be assumed to be the maximum range of α-particles in air?

• between 0 and 5 mm

• between 5 mm and 200 mm

• between 200 mm and 500 mm

• between 500 mm and 1000 mm

• 8 fm

• 6 fm

• 5 fm

• 4 fm

The intensity of light from a small lamp is 0.584 W·m⁻² at a distance 0.640 m from the lamp. What would be the expected intensity at a distance 0.960 m from the lamp?

• 0.220 W·m⁻²

• 0.260 W·m⁻²

• 0.389 W·m⁻²

• 0.876 W·m⁻²

A detector is exposed to a radioactive source. Fluctuations in the count-rate are observed. What do these fluctuations indicate about radioactive decay?

• It is random.

• It is spontaneous.

• It is exponential.

• It is non-linear.

In an experiment to measure the activity of a radioactive source, the measured activity should always be correct by

• adding the background count

• adding the background count rate

• subtracting the background count

• subtracting the background count rate

Two charged objects are pushed apart by a repulsive force that follows an inverse square law. At a certain distance, the repulsive force on each object is 0.080 N. What is the new force when the distance separating the objects is halved?

• 0.020 N

• 0.040 N

• 0.160 N

• 0.320 N