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  • Class 7 Science Study Material

An Educational platform for Preparation and Practice Class 7. Kidsfront provide unique pattern of learning Science with free online comprehensive study material in the form of QUESTION & ANSWER for each Chapter of Science for Class 7. This study material help Class 7, Science students in learning every aspect of Heat . Students can understand Heat concept easily and consolidate their learning by doing Online Practice Tests on Science ,Heat chapter repeatedly till they excel in Class 7, Heat . Free ONLINE PRACTICE TESTS on Class 7, Heat comprise of Hundreds of Questions on Heat , prepared by the highly professionals team. Every repeat test of Heat will have new set of questions and help students to prepare themselves for exams by doing unlimited Online Test exercise on Heat . Attempt ONLINE TEST on Class 7,Science ,Heat in Academics section after completing this Heat Question Answer Exercise.


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  • Topic wise:Heat preparation in the form of QUESTION & ANSWER.
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Heat
To search for targets and threats in the surrounding sea and air, submarines make use of

a) Kaleidoscopes.
b) Periscopes.
c) Magnifying glass.
d) Rear view mirror.



Answer
Solution
Correct Answer Is : Periscopes.
Solution Is : A periscope is an instrument which uses the principle of reflection of light for observation from a concealed position. A simple periscope has a tube and at each end of which plane mirrors are set parallel to each other at 45 degree angle. Using this instrument, we are able to see the objects at the surface of sea while we are in submarines.
Convex mirror

a) Has a reflecting surface that bulges inward.
b) Has a reflecting surface that bulges outward.
c) Is also called a converging mirror.
d) Is also called a plane mirror.



Answer
Solution
Correct Answer Is : Has a reflecting surface that bulges outward.
Solution Is : ?A convex mirror or diverging mirror is a curved mirror which has reflecting surface that bulges outward towards the light source.
Image formed by a plane mirror is

a) Real in nature.
b) Virtual in nature.
c) Diminished compared to the object size.
d) Enlarged compared to the object size.



Answer
Solution
Correct Answer Is : Virtual in nature.
Solution Is : An image formed by a plane mirror cannot be obtained on a screen and is called a virtual image. The image formed is erect, laterally inverted and its size is same as that of the size of the object.
An image formed by a plane mirror is

a) Upside down.
b) Equidistant from
c) Smaller than the object.
d) Bigger than the object.



Answer
Solution
Correct Answer Is : Equidistant from
Solution Is : An image formed by a plane mirror is of same size as that of the object. It is virtual, erect and the distance of it behind the mirror is same as the distance of an object in front of the mirror.
By using a convex mirror, we can see an image that is

a) Real, inverted and enlarged.
b) Virtual, erect and diminished.
c) Real, erect and diminished.
d) Virtual, erect and enlarged.



Answer
Solution
Correct Answer Is : Virtual, erect and diminished.
Solution Is : The images formed by convex mirror cannot be obtained on a screen but are formed in upright position and are very small in size. For example, the images formed by the side view mirror of a car are virtual, erect and diminished as these mirrors are convex in nature.
Transparent glassses which are thicker in the middle than at the edges are

a) Concave lenses.
b) Used in kaleidoscope.
c) Used in periscope.
d) Convex lenses.



Answer
Solution
Correct Answer Is : Convex lenses.
Solution Is : Transparent glasses which are thicker in the middle than at the edges are convex lenses. They are designed so as to converge the light passing through them to a point.
The nature and size of an image depend upon the

a) Time of conducting the experiment.
b) Position of the object.
c) Kind of the object.
d) Position of the object in case of mirrors only.



Answer
Solution
Correct Answer Is : Position of the object.
Solution Is : The nature and size of an image depend upon the position of the object. For example, in case of plane mirror, image is formed behind the mirror at a distance equal to the object distance in front of the mirror.
Concave lens is also known as

a) Diverging lens.
b) Converging lens.
c) Plane lens.
d) Magnifying lens.



Answer
Solution
Correct Answer Is : Diverging lens.
Solution Is : Concave lens is also known as a diverging lens because it diverges the light away from a point, i.e., the light bends outward.
Sunlight consists of

a) Black colour only.
b) Five colours.
c) Seven colours.
d) Blue colour.



Answer
Solution
Correct Answer Is : Seven colours.
Solution Is : Sunlight consists of seven colours. Sunlight (white light) when passed through a prism splits into seven rainbow colours proving that white colour is made up of seven colours.
The correct sequence of seven colours of a rainbow is

a) Blue, Orange, Red, White, Purple, Yellow, Green.
b) Violet, Blue, Indigo, Green, Red, Yellow, Orange.
c) Violet, Indigo, Blue, Green, Yellow, Orange, Red.
d) Violet, Red, Orange, Yellow, Green, Indigo, Blue.



Answer
Solution
Correct Answer Is : Violet, Indigo, Blue, Green, Yellow, Orange, Red.
Solution Is : The correct sequence of seven colours of a rainbow is Violet, Indigo, Blue, Green, Yellow, Orange, Red.
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