NEETPhysicsGravitation
Match List-I with List-II. R_E is the radius of the Earth. List-I List-II (A) Height above Earth's surface where weight of a body decreases by 75 % (I) R_E 4 (B) Height above Earth's surface where weight of a body decreases by 36 % (II) 3R_E 4 (C) Depth below Earth's surface where weight of a body decreases by 75 % (III) 9R_E 25 (D) Depth below Earth's surface where weight of a body decreases by 36 % (IV) R_E Choose
Options
- A(A)-(II), (B)-(III), (C)-(IV), (D)-(I)
- B(A)-(IV), (B)-(I), (C)-(II), (D)-(III)
- C(A)-(I), (B)-(IV), (C)-(III), (D)-(II)
- D(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
Correct answer
B. (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
Step-by-step solution
Let the weight on the surface be W = mg . For (A): Weight decreases by 75 % , so it becomes 25 % of W . W_h = W 4 g_h = g 4 Using g_h = g ( R_E R_E+h )^2 , we get 1 4 = ( R_E R_E+h )^2 1 2 = R_E R_E+h h = R_E . So, (A) matches (IV). For (B): Weight decreases by 36 % , so it becomes 64 % of W . W_h = 16W 25 g_h = 16g 25 Using g_h = g ( R_E R_E+h )^2 , we get 16 25 = ( R_E R_E+h )^2 4 5 = R_E R_E+h 4R_E + 4h = 5R_E h = R_E 4 . So, (B) matches (I). For (C): Weight decreases by 75 % , so it becomes 25 % of W . W_d = W