Answer:
PCBs have high electrical resistance and are excellent insulating materials.
Explanation:
Polychlorinated biphenyls [PCBs] are industrial chemical compounds made by man, which contains carbon, hydrogen and chlorine atoms. They can be used in the production of paints and dyes, heat transfer, etc.
There has been the ban on the use of these compounds because they are said to be very stable, and yield slowly to degradation by nature. They have low and not high electrical resistance.
Answer:
Scalar
Explanation:
A physical quantity that is completely described by its magnitude; examples of scalars are volume, density, speed, energy, mass, and time. Other quantities, such as force and velocity, have both magnitude and direction and are called vectors.
Answer: The frequency of the wave is 0.02 Hertz.
Explanation:
Frequency is a parameters which describe a wave. This is defined as the number of oscillations happening per unit second.
Mathematically,
In the question,
Number of oscillations happening per second = 50
Putting this value in above equation, we get:
Hence, the frequency of the wave is 0.02 Hertz.
B) The frequency will increase
C) The frequency will decrease
D) The frequency will increase or decrease depending on the diameter of the horn.
E) The frequency will remain same
Answer:
B) The frequency will increase
Explanation:
The length of the instrument is given by
Wavelength is given by
It can be seen that the length is inversely proportional to the frequency.
Here, the length of the trombone is decreasing so the frequency will increase.
The statement which best describes how heat flows is that the heat generally flows from a warmer object to a colder object. Therefore, the correct option is A.
The mechanism of heat flow significantly describes the transfer of heat energy or enthalpy from one object to another. It is transferred through the process of conduction, convection, and radiation.
The object that is warmer in appearance may accumulate heat in enough amounts. This leads to an increase in its temperature and energy, While the mechanism of heat transfer generally initiates this warmer object to a colder object by conduction.
To learn more about Heat flow, refer to the link:
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b. The Maunder minimum is unrelated to climate.
c. Changes in the Earth’s tilt correlate to changes in climate.
d. Changes in the Earth’s orbit correlate to changes in climate.
Maunder minimum is related to climate due to the unusually low sunspot activity correlates to unusually cold climatic events. The answer is letter A. It happened around 1645 and 1715 and also coincided with the phenomena ‘Little Ice Age’ (1500 – 1850) in the Northern Hemisphere.
Answer:
The correct option is D
Explanation:
Integumentary system consists of organs including the skin which is used in the excretion of sweat.
Digestive system consists of organs including the tongue, pancrease, gallbladder and liver. The liver for example regulates toxic substances in the body and excretes a substance known as bile.
Respiratory system consists of organs including the lungs which is used to breathe in oxygen and breathe out carbon dioxide.
Urinary system consists of the kidneys, urethra, bladder and ureters; they are involved in the excretion of urine.
Circulatory system consists of the blood, the blood vessels and heart. The circulatory system also assists in the removal of carbon dioxide from the body.
Answer: D
Explanation: