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21.

A solid body of constant heat capacity 1 j/oC is being heated by keeping it in contact with reservoirs in two ways

(i) Sequentially keeping in contact with 2 reservoirs such that each reservoir supplies the same amount of heat.

(ii) Sequentially keeping in contact with 8 reservoirs such that each reservoir supplies the same amount of heat.

In both the cases, body is brought from initial temperature 100oC to final temperature 200oC. Entropy change of the body in the two cases respectively , is

A) ln2, 4ln2

B) ln2, ln2

C) ln2, 2ln2

D) 2ln2, 8ln2

22.

From a solid sphere of mass M and radius R ,a cube of maximum possible volume is cut.Moment of inertia of cube about an axis passing through its centre and perpendicular to one of its face is

A) $\frac{MR^{2}}{32\sqrt{2}\pi}$

B) $\frac{MR^{3}}{32\sqrt{2}\pi}$

C) $\frac{4MR^{2}}{9\sqrt{3}\pi}$

D) $\frac{4MR^{2}}{16\sqrt{3}\pi}$

23.

Distance of centre of mass of a solid uniform cone from its vertex is z0.If the radius of its base is R and its height is h, then zis equal to

A) $\frac{h^{2}}{4R}$

B) $\frac{3h}{4}$

C) $\frac{h^{2}}{R}$

D) $\frac{h}{4}$

24.

A particle of mass m moving in the x-direction with speed 2v is hit by another particle of mass 2m moving in the y-direction with speed v .If the collosion is perfectly inelastic the percentage loss in the eneergy during the collosion is close to

A) 44%

B) 50%

C) 56%

D) 62%

25.

The period of oscillation of a simple pendulam is $T= 2\pi \sqrt{\frac{L}{g}}$.Measured value of L is 20.0 cm known to 1 mm accuracy and time for 100 oscillation  of the pendulam is found to be 90 s using  a wrist watch of 1 sresolution .The accurancy in the determination of g is

A) 2 %

B) 3 %

C) 1 %

D) 5 %

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