Section ? II

goldknight

Section 1

Only one correct +3 , -1

Focal length of a lens in water (m_w= 4/3 ) is equal to ?2 times its focal length (m_a = 1). The Refractive index of the material of lens is

(a) 1.2 (b) 1.5

(c) 1.3 (d) 1.25

A boy is standing on a cart moving along x-axis with the speed of 10 m/s . When the cart reaches the origin he throws a stone in the horizontal x-y plane , with the speed of 5 m/s with respect to himself at an angle q with the x-axis . It is found that the stone hits a ball lying at rest at a point whose co-ordinates are (Ö3 , 1) . The value of q is (gravitational effect is to be ignored).

(a) 30 (b) 60

( c) 90 (d) 120

A particle of mass m is moving in a circle of radius r. The centripetal acceleration of the particle varies with time according to the relation a_c=Kt² , where K is a positive constant and t is the time . The magnitude of the time rate of change of angular momentum of the particle about the centre of the circle is

(a) mKr (b) Ö (m²Kr³)

( c) Ö (mkr) (d) mkr²

A spherical cavity is created in a uniform solid sphere of mass M and radius R by removing part of the sphere. The radius of the cavity is r and its centre of mass is at a distance ?a? from the centre of the sphere. The gravitational field strength at the centre of the cavity is.

(a) (GM / R³) *a (b) (GM / R²) *a

( c)(GM / r³) *a (d) (GM / r²) *a

5. The kinetic energy of a non-relativistic electron increases by 2% then the de-Broglie wavelength

(a) increases by 1% (b) decreases by 2%

(c) decreases by 2% (d) increases by 2%

6. A radioactive element decays to one fourth of its initial value in time t. The ratio of its half life to its mean life is

(a) ln 2 / l² (b) ln 2 / l

(c) l * ln 2 (d) ln 2

7. In the figure shown internal resistance of each cell is 1 W. Potential difference across the terminals of the 2 V cell is

(a) 2.5 V (b) 1.5 V

(c) 2 V (d) 3.5 V

8. A particle is moving with a constant speed of p m/s on a circular track of radius

12 m . The Magnitude of its average acceleration for the time interval of 6 s is

(a) (p² / 12) m/s² (b) (p / 3Ö2) m/s²

(c) (p / 6) m/s² (d) 0 m/s²

9. In figure shown , radius of the limbs of the manometer are r1 and r2 (>r1) .

The surface tension of the liquid is T. The difference of the height of the liquid column

H is equal to (Assume that the angle of contact is zero).

(a) (2T / rg)( 1/r1 ? 1/r2 ) (b) (T / rg)( 1/r1 ? 1/r2 )

(c) (2T / rg)( 1/r1 + 1/r2 ) (d) (T / rg)( 1/r1 + 1/r2 )

Section ? II

+3 , -1

Assertion reason

Choose

(A) if Statement ?1 is True , Statement ?2 is true ; Statement ?2 is correct explanation for Statement ?1 .

(B) if Statement ?1 is True , Statement ?2 is true ; Statement ?2 is NOT correct explanation for Statement ?1 .

(C) Statement ?1 is True , Statement ?2 is False.

(D) Statement ?1 is False , Statement ?2 is True.

10. Statement ?1

In a system of particles, momenta of the individual particles can change even if no

external force is present.

because

Statement ?2

External force, i.e., forces exerted by other particles can cause changes in the momentum

of the particle.

11. Statement ?1

If a body (ball) is rolling on a surface without slipping , no frictional force acts on it.

because

Statement ?2

In the case of rolling without slipping, points of contact are at rest relative to each other.

12. Statement ?1

Torque acting on a body is defined as t=A x L (all vectors) , where A is a constant vector

and L is the angular momentum of the body. The magnitude of the angular momentum of

the body remains same.

because

Statement ?2

t is perpendicular to L and also perpendicular to w (also vector) , hence torque does not

deliver any power to the body.

13. Statement ?1

Weight of an object on earth is more at midnight than at noon.

because

Statement ?2

At noon gravitational pull on the object by the sun and that by the earth are

oppositely directed , and at midnight they are in same direction.

Section ?III

+4 , -1

Paragraph (I can provide only one paragraph quest here)

P_14-16 :Paragraph for Question Nos. 14 to 16

In the figure n mole of a monoatomic gas undergo the process ABC as shown on the adjacent PV diagram. The process AB is the isothermal and BC is isochoric. The temperature of the gas at A is T₀ . Total heat given to the gas during the process ABC is measured to be Q.

14. Temperature of the gas at C is equal to

(A) T₀ (B) 3T₀

(C) 6T₀ (D) 2T₀

15. Heat absorbed by the gas in the process

(A) 3nRT₀ (B) nRT₀

(C) 2nRT₀ (D) 6nRT₀

16. The average molar heat capacity of the gas in the process ABC is

(A) Q / nT₀ (B) Q / 2nT₀

(C) Q / 3nT₀ (D) 2Q / nT₀

Section ?IV

+6 , -0

Matrix-Match Type

20. Column I Column II

(A)Particle behavior of light (p) Reflection

(B)Electron microscope (q) Refraction

(C)X-ray photon (r) Interference

(D)Spectrum (s) Photoelectric effect

21. A uniform disc is acted upon by some forces and it rolls on a horizontal plank without

slipping from north to south. The plank , in turn lies on a smooth horizontal surface.

Column I Column II

(A)Frictional force on the disc by the surface (p) May be directed towards north

(B)Velocity of the lowermost point of the disc (q) May be directed towards south

(C)Acceleration of centre of mass f the disc (r) May be zero

(D)Vertical component of acceleration of (s) Must be zero

centre of mass

22. Some quantities related to the photoelectric effect are mentioned under Column I

and Column II. Match each quantity in Column I with the corresponding quantities

in Column II on which it depends.

Column I Column II

(A)Saturation Current (p) Frequency of light

(B)Stopping potential (q) Work function

(C)de-Broglie wavelength of photoelectron (r) Area of photo sensitive plate

(D)Force due to radiation falling on the (s) Intensity of light (at constant

photo plate frequency)

Answers (some ans might be wrong please discuss them and correct the ans)

1. (A) 2. (D) 3.(B) 4.(A) 5.(C) 6.(D) 7.(A) 8.(B)

9. (A) 10.(A) 11.(D) 12.(A) 13.(D) 14.(B) 15.(A) 16.(B)

20. (A) ? (p)(q)(s)

(B) ? (r)

(C) ? (p)(q)(r)(s)

(D) ? (q)

21. (A) ? (p)(q)(r)

(B) ? (p)(q)(r)

(C) ? (p)(q)(r)

(D) ? (s)

22. (A) ? (s)

(B) ? (p)(q)

(C) ? (p)(q)

(D) ? (p)(r)(s)

The three diagrams have been attached separately.

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Section ? II

Assertion reason

Statement ?2

Statement ?2

Statement ?2

Statement ?2

Section ?III

Section ?IV

Matrix-Match Type