Science Form3 Chap8 : Radioactivity

Who is the German physicist who discovered x-ray.

• John Dalton

• Wilhelm Conrad Roentgen

• Antoine Henri Becquerel

• Marie and Pierre Curie

He discovered radioactivity. He found uranium and unintentionally produced rays that can blacken a photographic plate even in the dark.

• Antoine Henri Becquerel

• Marie and Pierre Curie

• James Brooke

• J.J Thomsom

Which radiations have ionising power. [More than 1 answer]

• Gamma ray

• X-ray

• Microwave

• Infrared

Which elements are radioactive?

• Carbon-14

• Sodium-23

• Phosphorus-32

• Iodine-127

What is the SI unit for radioactivity?

• becquerel (Bq)

• watt (W)

• curie (Ci)

• $\frac{\mu Sv}{h}$

Which particles are positive ion?

• P

• Q

• R

• S

• T

Which particles are negative ion?

• P

• Q

• R

• S

• T

Which particles is neutral?

• P

• Q

• R

• S

• T

What is the formula of ion X?

• Br^-

• Br²⁺

• Br⁺

• Br^2-

Pa-234 decays to U-234 by emitting beta radiation. If the half-life of Pa-234 is 5.2 hours, what is the remaining mass of Pa-234 after 20.8 hours given its original mass is 32g.

• 2g

• 4g

• 8g

• 16g