CBSE Pathshala

1. Key terms: Arithmetic progression (A.P.) :- An A.P. is a list of numbers in which each term is obtained by adding a fixed number to the preceding term except the first term. This fixed number is called the common difference of the A.P. If a is first term and d is common difference of an A.P. , then the A.P is a , a +d , a+2d , 2+3d ….. The term of an a.p is denoted by and = a+(n-1) d , where a = first term and d = common difference. term from the end = l – (n-1) d , where l = last term. Three terms a-d , a , a+d are in A.P with common difference d. Four terms a-3d , a-d , a+d ,a+3d are in A.P with common diff. 2d . The sum of first n natural number is The sum of n terms of an A.P with first term a and common difference d is denoted by = { 2a+(n-1) d } also , = (a+l) where , l = last term. = - . Where = term of an A.P D = - . Where d = common difference of an A.P. 2. Let us denote the first term of an AP by a1, second term by a2 , . . ., nth t...

Q.1. What changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails dipped in copper sulphate solution for about 30 minutes? Ans: Iron nails get coated with a reddish brown substance. Copper sulphate solution becomes light green Q.2. A charged particle enters at right angles into a uniform magnetic field. What should be the nature of charge on the particle if it begins to move in a direction pointing vertically out of the page due to its interaction with the magnetic field ? Ans: Positive charge / Proton Q.3. What happens when an aqueous solution of sodium sulphate reacts with an aqueous solution of barium chloride? State the physical conditions of reactants in which the reaction between them will not take place. Write the balanced chemical equation for the reaction and name the type of reaction. Ans: (i) A white precipitate / Insoluble substance is formed. (ii) If the reactants are in solid state.  (iii) Na2SO4 + B...

Set-01 1. The class mark of the class 10 – 25 is :  (A) 17 (B) 18 (C) 17.5 (D) 15 2. Find the mean of the following frequency distribution [by assumed mean method] Class : 0 – 6 6 – 12 12 – 18 18 – 24 24 – 30  Frequency : 7 5 10 12 6 3. Find the mode of the following frequency distribution Class : 0 – 6 6 – 12 12 – 18 18 – 24 24 – 30 Frequency : 7 5 10 12 6 4. If the mean of the following distribution is 27, find the value of p Class : 0 – 10 ...