Nokea
What property of a substance remains constant regardless of changes in its shape or size?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: A
Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in its shape or size. Weight, density, and volume can all change depending on the conditions, but mass remains the same. For example, if you have a piece of clay and you shape it into a ball or flatten it into a pancake, the amount of clay (mass) will remain the same, even though the shape and size have changed. Weight is the force acting on an object due to gravity, which can vary depending on the gravitational pull. Density is the mass per unit volume, so it changes with variations in volume. Volume is the amount of space occupied by an object, which can change if the shape or size of the object is altered.
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What is the process of converting light energy into chemical energy called?
- A. Respiration
- B. Fermentation
- C. Photosynthesis
- D. Hydrolysis
Correct Answer: C
Rationale: - Respiration (Option A) is the process by which cells break down glucose to release energy.
- Fermentation (Option B) is an anaerobic process that also involves the breakdown of glucose to release energy.
- Hydrolysis (Option D) is a chemical process that involves the breakdown of molecules by adding water.
Photosynthesis (Option C) is the process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. This process is essential for the survival of plants and ultimately sustains life on Earth by providing oxygen for other organisms to breathe and serving as a source of energy in the food chain.
What is the difference between a sensory neuron and a motor neuron?
- A. Sensory neurons carry signals from sensory receptors towards the central nervous system, while motor neurons carry signals away from the central nervous system to muscles and glands.
- B. Sensory neurons control voluntary muscles, while motor neurons control involuntary muscles.
- C. Sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system.
- D. Sensory neurons detect light, while motor neurons detect sound.
Correct Answer: A
Rationale: Sensory neurons are responsible for carrying signals from sensory receptors towards the central nervous system (brain and spinal cord), allowing the brain to receive information about the external environment. On the other hand, motor neurons carry signals away from the central nervous system to muscles and glands, enabling the brain to control voluntary and involuntary movements. Choice B is incorrect because sensory neurons do not control muscles, and motor neurons control both voluntary and involuntary muscles. Choice C is incorrect as sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system. Choice D is incorrect because sensory neurons detect various stimuli such as touch, taste, smell, and sound, while motor neurons are not involved in detecting sensory stimuli.
Which of the following is a strong base commonly used in cleaning products?
- A. Sodium hydroxide (NaOH)
- B. Ammonium hydroxide (NHâ‚„OH)
- C. Calcium hydroxide (Ca(OH)â‚‚)
- D. Potassium hydroxide (KOH)
Correct Answer: A
Rationale: Sodium hydroxide (NaOH) is a strong base commonly used in cleaning products due to its effectiveness in breaking down grease and fats. It is known for its corrosive properties and is commonly found in drain cleaners and oven cleaners. While ammonium hydroxide, calcium hydroxide, and potassium hydroxide are also bases, they are not as strong as sodium hydroxide and are not as commonly used in cleaning products. Ammonium hydroxide is more commonly found in household cleaning products for its disinfectant properties, calcium hydroxide is used in agriculture and construction, and potassium hydroxide is often used in industries like soap manufacturing and biodiesel production.
Which of the following is a unit of power?
- A. Newton-meter (N·m)
- B. Joule (J)
- C. Watt (W)
- D. Kilogram (kg)
Correct Answer: C
Rationale: The correct answer is C: Watt (W). Power is the rate at which work is done or energy is transferred. The unit of power is the watt (W), named after James Watt, the inventor of the steam engine. A Newton-meter (N·m) is a unit of torque, Joule (J) is a unit of energy, and Kilogram (kg) is a unit of mass, not power. Therefore, choices A, B, and D are incorrect as they represent units of torque, energy, and mass, respectively, and not power.
What is the unit of force in the SI system?
- A. Newton (N)
- B. Kilogram (kg)
- C. Meter (m)
- D. Second (s)
Correct Answer: A
Rationale: The unit of force in the SI system is the Newton (N). It is defined as the amount of force required to accelerate a mass of one kilogram at a rate of one meter per second squared. In the SI system, force is measured in Newtons, not in kilograms, meters, or seconds. Choice B, Kilogram (kg), is incorrect because kilograms are units of mass, not force. Choice C, Meter (m), is incorrect because meters are units of length, not force. Choice D, Second (s), is incorrect because seconds are units of time, not force.