CBSE Class 12 Sample Paper for 2020 Boards

Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

(a) 0Β  Β  Β  Β  Β  Β  Β (b) 3Β  Β  Β  Β  Β  Β  Β (c) 6/β83Β  Β  Β  Β  Β  Β  Β  Β (d) 6

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Note : - This is similar to Misc 22 of NCERT β Chapter 11 Class 12

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Transcript

Question 9 What is the distance(in units) between the two planes 3x + 5y + 7z = 3 and 9x + 15y + 21z = 9 ? (a) 0 (b) 3 (c) 6/β83 (d) 6 Here, the two planes are parallel We know that Distance between two parallel planes Ax + By + Cz = π_1 and Ax + By + Cz = π_2 is |(π_π β π_π)/(β(π¨^π + π©^π + πͺ^π ) )| 3x + 5y + 7z = 3 Comparing with Ax + By + Cz = d1 A = 3, B = 5, C = 7, d1 = 3 9x + 15y + 21z = 9 3(3x + 5y + 7z) = 9 Dividing by 3 3x + 5y + 7z = 3 Comparing with Ax + By + Cz = d2 A = 3, B = 5, C = 7 , d2 = 3 So, Distance between the two planes = |(3 β 3)/β(3^2 + 5^2 + 7^2 )| = π }1 mark Hence, (A) is the correct option