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# IIT-JEE-Physics-2006

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5.     Given a sample of Radium-226 having half-life of 4 days. Find the probability, a nucleus distintegrates after 2 half lives.

(A)    1

(B)    ½

(C)    1.5

(D)    ¾

6.     Graph of position of image vs position of point object from a convex lens is shown. Then, focal length of the lens is

(A)    0.50 + 0.05 cm

(B)    0.50 + 0.10 cm

(C)    5.00 + 0.05 cm

(D)    5.00 + 0.10 cm

7.     A massless rod is suspended by two identical strings Ab and CD of equal length. A block of mass m is suspended from point O such that BO is equal to 'x'. Further, it is observed that the frequency of 1st harmonic (fundamental frequency) is AB is equal to 2nd harmonic frequency in CD. Then, length of BO is

(A)    L/5

(B)    4L/5

(C)    3L/4

(D)    L/4

8.     A system of binary stars of masses mA and mB are moving in circular orbits of radii rA and rB respectively. If TA and TB are the time periods of masses mA and mBrespectively, then

(A)   TA/TB =(rA/rB )3/2

(B)    TA > TB (if rA > rB)

(C)    TA > TB (if mA > mB)

(D)    TA = TB

9.     A solid sphere of mass M, radius R and having moment of inertia about an axis passing through the centre of mass as I, is recast into a disc of thickness t, whose moment of inertia about an axis passing through its edge and perpendicular to its plane remains I. Then, radius of the disc will be

(A) 2R/√15

(B) R√(2/15)

(C) 4R/√15

(D) R/4