## Kumar Ketan is teaching live on Unacademy Plus

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26.4k views 4.9 unacademy Kumar Ketan #16 Educator in IIT JEE #6 years teaching experience #IT JEE Physics #YouTuber (150k+ subs) #Unacademy educator(25kt lifetimeviews) #Under graduate topper Follow me on the Unacademy Learning App 1.3k 2 26 Followers Following Courses Get updates about new courses Watch all my lessons .Download slides and watch offline Lists (1) Kumar Ketan HINDI IIT JEE Physics by Kumar Ketan for lIT JEE 8 4 saves Kumar Ketan

IIT JEE 2017 PHYSICS Q. #1 to Q. #30 INDIAN IAN INSTITUTE Complete Paper Solution

Question 7 The variation of acceleration due to gravity g with distance d from centre of the earth is best represented by (R Earth's radius):

9 Sol. 9. d=R Variation of g inside earth surface Gm Gm Gm

Question 8 A copper ball of mass 100 gm is at a temperature t. It is dropped in a copper calorimeter of mass 100 gm, filled with 170 gm of water at room temperature. Subsequently, the temperature of the system is found to be 75 C. T is given by: (Given : room temperature 30 C, specific heat of copper 0.1 cal/gm C) (1) 800 C (2) 885 C (3) 1250 C (4) 825 C

Sol. 100 x 0.1 x (t-75) = 100 x 0.1 x 45 + 170 x 1 x 45 10t-750 = 450 + 7650 10t = 1200 7650 10t 8850 t = 885 C

Question9 An external pressure P is applied on a cube at O'C so that it is equally compressed from all sides. K is the bulk modulus of the material of the cube and a is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by (1)P/ (2)P/a K (3)3/PK a (4) 3PK a

V K _3 AV Vo