Nursing Elites

1. Which type of radiation emits helium ions and can be stopped by a piece of paper?

• A. Beta radiation
• B. Alpha radiation
• C. Gamma radiation
• D. X-ray radiation

Correct answer: B

Rationale: Alpha radiation emits helium ions, which are helium nuclei without electrons, making them positively charged. These ions are relatively large and heavy compared to beta and gamma radiation. Due to their size and charge, alpha particles interact strongly with matter and are easily stopped. A piece of paper or even human skin can effectively block alpha radiation. Therefore, alpha radiation is the type of radiation that can be stopped by a piece of paper. Beta radiation consists of fast-moving electrons and can penetrate further into materials than alpha radiation, thus not stopped by a piece of paper. Gamma radiation is highly penetrating and requires dense materials like lead or concrete to block it effectively. X-ray radiation, similar to gamma radiation, is also highly penetrating and cannot be stopped by a piece of paper.

2. If electrons are shared equally in a covalent bond, the bond is classified as what?

• A. Polar
• B. Non-polar
• C. Ionic
• D. Hydrogen

Correct answer: B

Rationale: The correct answer is B: Non-polar. In a non-polar covalent bond, electrons are shared equally between the atoms involved, leading to a balanced distribution of charge and no significant difference in electronegativity between the atoms. This equal sharing results in a non-polar bond. Choices A, C, and D are incorrect because a polar bond involves an unequal sharing of electrons, an ionic bond is formed by the transfer of electrons, and a hydrogen bond is a specific type of non-covalent bond.

3. Which type of change occurs when no change is made to the chemical composition of a substance?

• A. Chemical
• B. Physical
• C. Nuclear
• D. Mechanical

Correct answer: B

Rationale: A physical change refers to alterations in the state of matter without modifying the chemical composition of the substance. Examples of physical changes include changes in state (solid, liquid, gas), shape, size, or phase. In a physical change, the substance may look different or behave differently, but its chemical structure remains the same. On the other hand, chemical changes involve the breaking and forming of chemical bonds, resulting in the creation of entirely new substances with different chemical properties. Nuclear changes involve alterations in the nucleus of an atom, such as radioactive decay. Mechanical changes refer to changes in the position or motion of an object caused by applied forces, like pushing, pulling, or twisting.

4. What is the boiling point of water in °C?

• A. 90°C
• B. 100°C
• C. 95°C
• D. 80°C

Correct answer: B

Rationale: The correct answer is 100°C. The boiling point of water in Celsius is 100°C, which is standard at sea level. This is the temperature at which water changes from a liquid to a gas phase under standard atmospheric pressure. Choice A (90°C), Choice C (95°C), and Choice D (80°C) are incorrect because they do not represent the standard boiling point of water at sea level.

5. Which state of matter has a definite volume but takes the shape of its container?

• A. Gas
• B. Liquid
• C. Solid
• D. Plasma

Correct answer: B

Rationale: The state of matter that has a definite volume but takes the shape of its container is a 'Liquid.' Liquids have a fixed volume but can change their shape to fit the container they are in. This property distinguishes liquids from solids, which have both a definite shape and volume, and gases, which do not have a fixed volume or shape. Therefore, the correct answer is 'Liquid.' Choice A, 'Gas,' is incorrect because gases do not have a definite volume or shape. Choice C, 'Solid,' is incorrect as solids have a definite shape and volume. Choice D, 'Plasma,' is incorrect because plasma is a state of matter where atoms have been ionized and do not have a fixed volume or shape.

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