Nokea
What is the speed of the wave?
- A. 1.5cm/s
- B. 3.0cm/s
- C. 300 cm/s
- D. 600 cm/s
Correct Answer: D
Rationale: The correct answer is D: 600 cm/s. The speed of a wave is determined by the formula speed = frequency x wavelength. Given that the frequency and wavelength are constant, the only way to increase the speed is to increase the frequency or the wavelength. Since both frequency and wavelength are fixed, the speed can only be increased by increasing both. Choice D, 600 cm/s, is double the speed of choice C, 300 cm/s, which indicates that both frequency and wavelength have been doubled, leading to the correct answer. Choices A and B are too low to be correct, as they are not consistent with the principles of wave speed calculation.
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Which row identifies the chemical product of the fuel cell and the type of energy used to power the vehicles?
- A. hydrogen, electrical
- B. hydrogen, thermal
- C. water, electrical
- D. water, thermal
Correct Answer: C
Rationale: The correct answer is C because in a fuel cell, the chemical product is water (H2O) produced from the reaction of hydrogen and oxygen, and the energy used to power the vehicles is electrical energy generated from the electrochemical reaction in the fuel cell. Choice A (hydrogen, electrical) is incorrect because hydrogen is the input fuel, not the output product. Choice B (hydrogen, thermal) is incorrect because thermal energy is not the primary form of energy produced in a fuel cell. Choice D (water, thermal) is incorrect because while water is the product, the energy produced is electrical, not thermal.
Identify a hormone that increases metabolic rate.
- A. thyroid hormone
- B. calcitonin
- C. aldosterone
- D. parathyroid hormone
Correct Answer: A
Rationale: The correct answer is A: thyroid hormone. The thyroid hormone plays a crucial role in regulating metabolism by increasing the body's metabolic rate. It accomplishes this by stimulating the production of proteins that control the rate at which cells use energy. Calcitonin (B) is involved in regulating calcium levels in the blood, not metabolic rate. Aldosterone (C) is a hormone that regulates electrolyte balance and blood pressure. Parathyroid hormone (D) regulates calcium and phosphorus levels in the blood, not metabolic rate. Thus, the correct choice is thyroid hormone as it directly affects metabolic rate.
The transcription of new messenger RNA is a function of __________.
- A. pancreatic hormones
- B. steroid hormones
- C. catecholamines
- D. pituitary gland hormones
Correct Answer: B
Rationale: The correct answer is B: steroid hormones. Steroid hormones are known to regulate gene expression by binding to specific receptors and influencing transcription processes. They can directly affect the transcription of new messenger RNA in the cell. Pancreatic hormones (A), catecholamines (C), and pituitary gland hormones (D) are not directly involved in the transcription of new messenger RNA. Pancreatic hormones primarily regulate blood sugar levels, catecholamines are involved in the fight-or-flight response, and pituitary gland hormones regulate various functions such as growth, reproduction, and metabolism.
Which drug is most likely to cause muscle tremor:
- A. Ipratropium
- B. Terbutaline
- C. Atenolol
- D. Nicotinic acid
Correct Answer: B
Rationale: The correct answer is B: Terbutaline. Terbutaline is a beta-2 adrenergic agonist used as a bronchodilator. It can stimulate beta-2 receptors in skeletal muscle, leading to muscle tremors as a common side effect. Ipratropium (A) is an anticholinergic bronchodilator and typically does not cause muscle tremors. Atenolol (C) is a beta-blocker and is not associated with muscle tremors. Nicotinic acid (D) is used to treat dyslipidemia and does not commonly cause muscle tremors. Therefore, Terbutaline is the most likely drug to cause muscle tremor among the options provided.
Adrenaline can produce all of the following effects EXCEPT:
- A. Relaxation of bronchial muscle
- B. Increases cardiac contractility
- C. Increases intestinal motility
- D. Increases sweat secretion
Correct Answer: C
Rationale: Adrenaline, also known as epinephrine, is a hormone that activates the fight-or-flight response. It causes bronchial muscle relaxation (A), increases cardiac contractility (B), and increases sweat secretion (D) to prepare the body for action. However, adrenaline inhibits intestinal motility (C) to conserve energy for vital functions during stressful situations. Therefore, the correct answer is C because adrenaline does not increase intestinal motility. Relaxation of bronchial muscle, increased cardiac contractility, and increased sweat secretion are all effects of adrenaline, making choices A, B, and D incorrect, respectively.