Chapter 8 Radioactivity

Who is the scientist's name is used as the radioactivity S.I. unit?

• Wilhelm Roentgen

• Henri Becquerel

• Pierre Curie

• Marie Curie

50% of cobalt-60 atom decays after 5 years. Calculate the mass of cobalt-60 after 20 years, given that its original mass is 16g.

• 1g

• 2g

• 3g

• 4g

Which statement is true about radioactive decay?

• A random and non-spontaneous process

• A random and spontaneous process

• The stable nucleus becomes an unstable nucleus

• Does not emit radioactive radiation

The following radioactive radiation shall be transmitted when a radioactive material decay except

• Alpha particle

• Beta Particle

• Gamma-ray

• Cosmic ray

Which of the following device is used to measure the radiation dose?

• Ammeter

• Voltmeter

• Dosimeter

• Multimeter digital

Which of the following is/are ionising radiation?

• Infrared

• X-ray

• Gamma-ray

• visible light

• Beta ray

Which of the following is/are the man-made source of ionising radiation?

• nuclear accident

• cosmic ray

• nuclear test

• radioisotope for medical purpose

Diagram shows atom X. Given p is proton while n is neutron. What can you conclude about atom X?

• Formed positive ion

• Formed negative ion

• It is a neutral atom

• Contrary to Dalton's Atomic theory

Why are fruits preserved using gamma rays are safe to eat?

• The dosage used is at the safe level

• Gamma-ray from safe radioactive material is used

• Gamma-rays are only emitted for 1 second

• Gamma-rays are actually not harmful to health

Diagram shows the use of a radioactive substance in controlling the thickness of the paper. Which of the following is used to control the thickness of paper?

• X-ray

• Alpha ray

• Beta ray

• Gamma-ray