Q1. What is the process by which unstable atomic nuclei emit radiation?
a) Nuclear fusion
b) Nuclear fission
c) Radioactivity
d) Nuclear transmutation
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Correct Answer: c) Radioactivity
Explanation: Radioactivity is the spontaneous emission of radiation from the unstable atomic nuclei of certain elements in order to achieve a more stable configuration.
Q2. Which type of radiation consists of high-energy photons without mass or charge?
a) Alpha radiation
b) Beta radiation
c) Gamma radiation
d) Neutron radiation
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Correct Answer: c) Gamma radiation
Explanation: Gamma radiation consists of high-energy photons emitted from the nucleus during radioactive decay. Unlike alpha and beta radiation, gamma radiation has no mass or charge.
Q3. What type of radioactive decay involves the emission of an alpha particle?
a) Alpha decay
b) Beta decay
c) Gamma decay
d) Electron capture
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Correct Answer: a) Alpha decay
Explanation: Alpha decay occurs when an unstable nucleus emits an alpha particle, consisting of two protons and two neutrons, reducing the atomic number of the parent nucleus by 2 and the mass number by 4.
Q4. Which of the following particles has the highest ionizing power?
a) Alpha particle
b) Beta particle
c) Gamma ray
d) Neutron
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Correct Answer: a) Alpha particle
Explanation: Alpha particles have the highest ionizing power among the options listed. They are relatively heavy and carry a double positive charge, leading to significant ionization of surrounding atoms.
Q5. What type of radiation can be stopped by a sheet of paper or clothing?
a) Alpha radiation
b) Beta radiation
c) Gamma radiation
d) Neutron radiation
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Correct Answer: a) Alpha radiation
Explanation: Alpha radiation consists of relatively heavy alpha particles that can be stopped by a sheet of paper or clothing due to their low penetrating power.
Q6. Which type of radioactive decay involves the conversion of a neutron into a proton and the emission of an electron?
a) Alpha decay
b) Beta decay
c) Gamma decay
d) Positron emission
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Correct Answer: b) Beta decay
Explanation: Beta decay occurs when a neutron in the nucleus is converted into a proton, emitting an electron (beta particle) and an antineutrino.
Q7. What is the half-life of a radioactive substance?
a) The time taken for half of the substance to decay
b) The time taken for the substance to become stable
c) The time taken for the substance to emit radiation
d) The time taken for the substance to disintegrate completely
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Correct Answer: a) The time taken for half of the substance to decay
Explanation: The half-life of a radioactive substance is the time it takes for half of the radioactive nuclei in a sample to decay into more stable forms.
Q8. What is the process by which unstable atomic nuclei lose energy by emitting radiation?
a) Nuclear fusion
b) Nuclear fission
c) Radioactivity
d) Nuclear transmutation
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Correct Answer: c) Radioactivity
Explanation: Radioactivity is the process by which unstable atomic nuclei spontaneously emit radiation in the form of alpha particles, beta particles, or gamma rays to achieve a more stable configuration.
Q9. Which type of radiation consists of fast-moving electrons?
a) Alpha radiation
b) Beta radiation
c) Gamma radiation
d) Neutron radiation
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Correct Answer: b) Beta radiation
Explanation: Beta radiation consists of fast-moving electrons emitted from the nucleus during beta decay, where a neutron is converted into a proton.
Q10. What is the effect of alpha radiation on living tissues?
a) It has high penetration power
b) It causes mild tissue damage
c) It is highly damaging to living tissues
d) It has no effect on living tissues
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Correct Answer: c) It is highly damaging to living tissues
Explanation: Alpha radiation is highly damaging to living tissues when it enters the body, as it can ionize atoms along its path, causing severe cellular damage and increasing the risk of cancer.