CLASS 10TH DAY 3
INTRODUCTION
Mirror । rorriM
Everyday we see ourselves in the mirror and adore ourselves. But do you know what is the science behind mirrors?
The image of an object as seen in a mirror is its mirror reflection or mirror image. In such an image, the right side of the object appears on the left side and vice versa. A mirror-image is therefore said to be laterally inverted and the phenomenon is called the lateral inversion.
Some letters don’t change upon reflection. In other words, they are the same as that of their Mirror Images. The letters having identical mirror images are A, H, I, M, O, T, U, V, W, X, Y. Similarly, in small letters we have i, l, o, v, w, and x that have the same Mirror Image as that of their original images. The number 1 and 8 are the only two numbers with their identical mirror images.
Why is AMBULANCE written inverted on emergency vehicles?
It is because the driver of the front vehicle can easily see and figure out that an emergency vehicle (AMBULANCE) is coming and this helps the driver to respond fast and he can give way to the AMBULANCE.
The number 1 and 8 are the only two numbers with their identical mirror images.
The world of mirrors is so fascinating, let’s solve some more examples to understand the phenomena behind lateral inversion.
Example 1. Choose the alternatives which closely resembles the mirror image of the given combination.
Solution: (b) Here, the mirror is placed vertically on the RHS on the question figure. Hence, only the figure given in answer figure (b) would be obtained as the correct mirror image.
Example 2.Choose the alternative which most closely resembles the mirror image of the given combination.
Example 3. A clock seen through a mirror shows quarter to three. What is the correct time shown by the clock?
(a) 8 : 15 (b) 9 : 12 (c) 8 : 17 (d) 9 : 15
Solution: (d) Here,
It is clear from Fix. (X) that if seen through a mirror the time indicated by clock is 2 .45. When the mirror is placed vertically at AB, the mirror image i.e., Fig. (Y) shows the actual time in the clock i.e., (9 : 15).
Example 4. Choose the correct mirror image from the answer figures (a), (b), (c) and (d).
Solution: (b) Here, the mirror is placed horizontally at AB on the top of the question figure.Hence only answer figure (b) is the vertically inverted form of question figure in which top and bottom interchange places while LHS and RHS remain the same.
Mirror mirror on the wall, what do you want to say to us all ?
Here is a small quiz to test your understanding. Try to attempt all the questions and get the highest marks possible.
Intro to Periodic table
The Periodic table which we study today is the modern periodic table. The modern periodic table lists elements by atomic number, which is the number of protons in every atom of that element. Atoms of an atomic number may have varying numbers of neutrons (isotopes) and electrons (ions), yet remain the same chemical element.
Before we proceed further we should look at the definition of atom and element.
Atom: Atom is the smallest building block of matter.
Element: An element is a substance made up of only one kind of atom.
This is the representation of an element in periodic table, at the top is atomic number, then symbol of element, and atomic mass at the bottom.
Elements in the periodic table are arranged in periods (rows) and groups (columns). Each of the seven periods is filled sequentially by atomic number. Groups include elements having the same electron configuration in their outer shell, which results in group elements sharing similar chemical properties.
There are certain elements which are separately mentioned at the bottom of the Periodic table, as you can see in the image above. These elements are known as lanthanides and actinides.
The lanthanides are the elements with atomic numbers from 57 to 71.
Actinides are the elements with atomic numbers from 89 to 103.
The elements of Group 1 and Group 2 of the modern periodic table are called S block elements. The two types of s block elements are possible i.e. the elements with one electron (s1) or the elements with two electrons (s2) in their s-subshell.
The p-block elements are found on the right side of the periodic table. They include the boron, carbon, nitrogen, oxygen and flourine families in addition to the noble gases. The noble gases have full p-orbital’s and are nonreactive.
In the next discussion on periodic table, we will give you mnemonics to remember the Periodic table. We will restrict ourselves to s and P block elements and which will be more than enough at this point of time.
Sudoku
Sudoku is a puzzle that has enjoyed worldwide popularity since 2005. To solve a Sudoku puzzle, one needs to use a combination of logic and trial-and-error.
The standard version of Sudoku consists of a 9×9 square grid containing 81 cells. The grid is subdivided into nine 3×3 blocks. Some of the 81 cells are filled in with numbers from the set {1,2,3,4,5,6,7,8,9}. These filled-in cells are called givens. The goal is to fill in the whole grid using the nine digits so that each row, each column, and each block contains each number exactly once. We call this constraint on the rows, columns, and blocks the One Rule. Learn to solve the sudoku quickly by clicking below . Happy Solving…
We hope you have now learnt the way to solve the sudoku , now click on the below link and solve a sudoku.👇 👇
Puzzles
Its fun time now, try solving these logic puzzles.
THINK OUT OF THE BOX - Math riddles
People enjoy activities such as games, magic shows, contests, and puzzles. Therefore, it is not surprising to find students enjoying similar activities based on mathematics. Here are some math riddles to make you think out of the box.
