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On January 25, 2024, 11:35 AM

Exercise 15.4 - Chapter 15 Visualising Solid Shapes class 7 ncert solutions Maths - SaraNextGen [2024]


Question 1:

A bulb is kept burning just right above the following solids. Name the shape of the shadows obtained in each case. Attempt to give a rough sketch of the shadow. (You may try to experiment first and then Answer these Questions).

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/45/1869/Chapter%2015_html_2665e0f9.jpg

Answer:

The shapes of the shadows of these figures will be as follows.

(i) A ball

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/45/1869/Chapter%2015_html_5ed3cae2.jpg

The shape of the shadow of a ball will be a circle.

(ii) A cylindrical pipe

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/45/1869/Chapter%2015_html_m46c5fd0d.jpg

The shape of the shadow of a circular pipe will be a rectangle.

(iii) A book

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/45/1869/Chapter%2015_html_m75d313af.jpg

The shape of the shadow of a book will be a rectangle.

Question 2:

Here are the shadows of some 3−D objects, when seen under the lamp of an overhead projector. Identify the solids (s) that match each shadow. (There may be multiple Answers for these!)

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/45/1871/Chapter%2015_html_m2c19a8c0.jpg

Answer:

The given shadows can be obtained in case of the following objects.

1. Compact disk

2. A dice

3. Triangular pyramid

4. Note Book

Question 3:

Examine if the following are true statements:

(i) The cube can cast a shadow in the shape of a rectangle.

(ii) The cube can cast a shadow in the shape of a hexagon.

Answer:

A cube can cast shadow only in the shape of a square. Therefore, any other shapes are not possible.

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