HSC Physics Module 8: From the Universe to the Atom

In which region would a star have the same surface temperature as a star on the main sequence?

• P

• Q

• R

• S

The Hertzsprung-Russell diagram shown is used to classify stars.

Stars in region S of the diagram are much dimmer than other stars in the same spectral class. What property of the stars in region S explains their relatively low luminosity?

• They are cooler than other stars.

• They have a smaller mass than other stars.

• They have a smaller surface area than other stars.

• They are further away from Earth than other stars.

After DC voltage was applied to an apparatus containing hydrogen gas, the hydrogen separated into streams of oppositely charged particles. What could be concluded from this observation?

• Hydrogen gas conducts electricity.

• Hydrogen is the simplest element

• Hydrogen atoms have components.

• Hydrogen atoms have a neutral charge.

• A

• B

• C

• D

In an experiment, an electrically charged oil drop was suspended in air by an electric field. The electric field could be adjusted to balance the weight of the oil drop. If more drops were suspended and measurements taken, which of the following properties would all of the oil drops be observed to have in common?

• The mass of each drop would be a multiple of a fundamental mass

• The mass of each drop would be the same as each of the other drops

• The charge of each drop would be a multiple of a fundamental charge

• The charge of each drop would be the same as each of the other drops.

• 1 to 3

• 3 to 1

• 2 to 4

• 4 to 2

What is the approximate value of the decay constant, in year^–1, for strontium-90?

• 0.006

• 0.011

• 0.014

• 0.025

• A

• B

• C

• D

• A

• B

• C

• D

A patient is given an injection containing 6.0 × 10^–18 kg of radioactive technetium-99m which has a half-life of 6 hours. How much remains undecayed when a scan is taken 4 hours later?

• 2.1 × 10^–18 kg

• 3.0 × 10^–18 kg

• 3.8 × 10^–18 kg

• 4.0 × 10^–18 kg