ingwish between.
1) Umbra and penumbra
99 ) Metals and non-metal
Q.3.A] Answer the question in short (any 5)
1) Why is the shadow of a bird flying high not seen on
2) Write any 5 uses of Ultrasonic sound.
3) Why is magnetic needle used in compass?
4) What points should be considered before a sky wat
5) What is meant by fossil fuel? What are their types?
6) Why is the diversity of plants and animals in the for
B] Explain the terms.(any 2)
2) An eclipse
Answers
UMBRA
In physics, the umbra refers to the darkest part of the shadow. If you aim a light source directly at an object, the blackest portion of the shadow directly behind the object is the umbra of the shadow. In astronomy, if the sun is shining directly on the western hemisphere of the earth, the eastern hemisphere is bathed in darkness, and objects behind the earth (such as the moon or other planets) are in the earth’s umbra.
PENUMBRA
Penumbra refers to the lighter shading that hangs on the outskirts of the umbra. The penumbra is not a true shadow. The Lighting Design and Simulation Knowledgebase describes the penumbra as a gradient: The shading gradually lessens from shadow to light as the penumbra stretches away from the umbra.
METALS AND NONMETALS
Metals are malleable and ductile. .Non- metals are brittle (break easily). They are neither malleable nor ductile.
Metals are malleable and ductile. .Non- metals are brittle (break easily). They are neither malleable nor ductile.Metals are good conductors of heat and electricity. Non-metals are bad conductors of heat and electricity. Except for graphite which is a good conduction of electricity.
Metals are malleable and ductile. .Non- metals are brittle (break easily). They are neither malleable nor ductile.Metals are good conductors of heat and electricity. Non-metals are bad conductors of heat and electricity. Except for graphite which is a good conduction of electricity. Metals are lustrous and can be polished.
Metals are malleable and ductile. .Non- metals are brittle (break easily). They are neither malleable nor ductile.Metals are good conductors of heat and electricity. Non-metals are bad conductors of heat and electricity. Except for graphite which is a good conduction of electricity. Metals are lustrous and can be polished. Non-metals are non-lustrous (dull) and cannot be polished. Except for iodine
Metals are malleable and ductile. .Non- metals are brittle (break easily). They are neither malleable nor ductile.Metals are good conductors of heat and electricity. Non-metals are bad conductors of heat and electricity. Except for graphite which is a good conduction of electricity. Metals are lustrous and can be polished. Non-metals are non-lustrous (dull) and cannot be polished. Except for iodineMetals are solids at room temperature.Except for mercury which is a liquid metal. Non-metals may be solid, liquid or gases at the room temperature.
Metals are malleable and ductile. .Non- metals are brittle (break easily). They are neither malleable nor ductile.Metals are good conductors of heat and electricity. Non-metals are bad conductors of heat and electricity. Except for graphite which is a good conduction of electricity. Metals are lustrous and can be polished. Non-metals are non-lustrous (dull) and cannot be polished. Except for iodineMetals are solids at room temperature.Except for mercury which is a liquid metal. Non-metals may be solid, liquid or gases at the room temperature. Metals are strong and tough. Non-metals are not strong or tough.
ANSWER IN SHORT
A.1) Birds flying high in the sky do cast their shadow but because they are shading an area that is very tiny, the shadow is not visible. The higher the bird flies, the smaller the shadow it casts. Answer: ... And, because of geometric optics, the shadow will be more diffuse when the object is higher in the sky.
A.2) Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws.
A.3) The magnetic needles used in compasses are Magnetic in nature because the Earth has a strong magnetic dipole due to its dynamo effect which creates the magnetic field around the earth's surface
A.4) The points that should be considered before a sky watch: 1) proper arrangement of telescope and other equipments. 2) clear cloud free sky. 3) proper altitude and location of the observatory.
A.5) Fossil fuels principally consist of carbon and hydrogen bonds. There are three types of fossil fuels which can all be used for energy provision; coal, oil and natural gas. Coal is a solid fossil fuel formed over millions of years by decay of land vegetation.
A.6) It is only obvious that the diversity in plant and animals will decrease due to the increase in amount of population, reckless cutting of trees or deforestation and rise in the pollution leading to global warming.
A.7)An eclipse is the result of either an occultation (completely hidden) or a transit (partially hidden). The term eclipse is most often used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon moves into the Earth's shadow.
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