किरण प्रकाशिकी एवं प्रकाशिक यंत्र | Class 12 NCERT भौतिक विज्ञान | 10 AM Class By Shubham Sir | L6 |

There are 5 students in class 10, 6 students in class 11 and 8 students in class 12. If the number of ways, in which 10 students can be selected from them so as to include at least 2 students from each class and at most 5 students from the total 11 students of class 10 and 11 is 100 k, then k is equal to _______.

(i) In how many ways a committee of 4 members out of 5 gents and 6 ladies can be formed if there is at least one lady in the committee? (ii) From a class of 12 boys and 8 girls, 10 students are to be chosen for a competition, including at least 4 boys and 4 girls. The two boys whho won the prizes last year should be included. In how many was can this selection be made?

In class 12 there are 8 students. In class 11 there are 6 students .In class 10 there are 5 students . Total ways of selecting 10 students , such that there are at least 2 students from each class and at most 5 students from 11 students of Class 10 and 11 combined is 100k. Then find value of k

Consider the marks, out of 100, obtained by 51 students of a class in a test, given in Table 14.9. M a r k s"N u m b e r o f S t u d e n t s"0-10 5 10-20 10 20-30 4 30-40 6 40-50 7 50-60 3 60-70 2 70-80 2 80-90 3 90-100 9Tot a l 51 Draw a freque

Thirty children were asked about the number of hours they watched TV programmes in the previous week. The results were found as follows: 1 6 2 3 5 12 5 8 4 8 10 3 4 12 2 8 15 1 17 6 3 2 8 5 9 6 8 7 14 12 (i) Make a grouped frequency distribution table for this data, taking class width 5 and one of the class intervals as 5 - 10. (ii) How many children watched television for 15 or more hours a week?

The distance (in km) of 40 engineers from their residence to their place of work were found as follows: 5 3 10 20 25 11 13 7 12 31 19 10 12 17 18 11 32 17 16 2 7 9 7 8 3 5 12 15 18 3 12 14 2 9 6 15 15 7 6 12 Construct a grouped frequency distribution table with class size 5 for the data given above taking the first interval as 0-5 (5 not included). What main features do you observe from this tabular representation?

One day Vabhav was performing experiments in the science laboratory based on the of chemical combination. Just then his chemistry teacher, Mr. Rajeev, came into the laboratory. Mr. Rajeev told Vaibhav that in an experiment conducted byby a class IX student when 10.6 g of sodium carbonate was reacted with 12.0g of ethanoic acid in a closed flask, then 16.4 g of sodium ethanoate, 4.4 g of carbon dioxide and an unknown mass of substances Y were produced. Mr. Rajeev asked Vaibhav to make use of this information and answer the following questions : (a) Write a word equation for the reaction which takes place on reacting sodium carbonate and ethanoic acid (b) Which is the substance Y which is produced in this reaction ? (c) What mass of substance Y is produced in this reaction ? (d) Which law of chemical combination has been made use of in calculating the mass of substance Y ? State this law (e) What values are displayed by Vaibhav in this eposide ?