Sample test forJEE -advance op-mag-mech-2 @viresh

7/30/2019 Sample test forJEE -advance op-mag-mech-2 @viresh

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1 / rev pt-11/ iit-jee-2008/ magnetism,optics& mechanics

PT-12 for AIPMT/AIEEE& IIT JEE-2008for 12++ scholars

mag+optics+mech( sep -2)

p q r sABCD

1-In the circuit shown initially the switch is open and thereexist no current any where. The switch is closed at time t =0. R1The emf of the cell is E.In the following column I, statementsabout the physical quantities related to the circuit,

are mentioned . In the column II some values or features L R2of the corresponding quantities are given. Match theitems in column I with the items in the column II. SThe answer is to be given in the matrix by bubbling the matrix correctly.

Column I Column II(A) Current in the R2 (p) decreases with time t(B) Potential across the inductor (q) at t=0+ , is function ofR1/ R2(C) current in the inductor (r) at time t , is independent ofR2

(D) current through the cell (s) increases with time t ,and finally becomesconstant

Linked Comprehension typeThis section contains four paragraphs. Each paragraph is followed by few

questions with multiple options for their answers. Choose the only one option

which is most correct.

P2- 4: Paragraph for the Q.Nos 2 to 4

There is a conducting rectangular loop ofN turns. The side lengths of theloop are b and c . Resistance of the loop is R.. The loop is being rotatedby a person with constant angular velocity about one of the side, whoselength is b . A uniform magnetic field B is applied over the loop from timet=0, when the plane of the loop is perpendicular to the field B.2-The induced current in the loop at time t is proportional to(a) sin t (b) cos t (c) sin 2t (d) none of these3- The torque on the loop due to magnetic forces , at time t is , proportional to(a) sin t (b) cos t (c) sin 2t (d) sin2t4 - The heat produced in the loop in one revolution of the loop, will be(a) zero (b) proportional to N(c) proportional to 2 (d) proportional to


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P5- 7: Paragraph for the Q.Nos 5 to 7A proton and an alpha particle , both accelerated up to same potential , enetrs a

region in x-y plane , moving along positive x- direction. There is a uniformmagnetic field in the region directed along positive z-direction. Both particles areseen to follow circular path. { Neglect any mutual force between the two particles}5- Ratio of the magnetic force on the proton to that on alpha, is(a) 1:1 (b) 1:2 (c) 1:2 (d) 1 :4

6- The angular speed of the two particles will be in ratio(a) 2 : 1 (b) 1:1 (c) 4 : 1 (d) 2 :1

7- The angular momentum of the two particles about their centers will be in ratio(a) 1 : 2 (b) 1 : 1 (d) 1 :2 (d) 1 : 4

P8-11 : Paragraph for the Q.Nos : 8 to 11A uniform rod of mass 4 M and length L is pivoted at its center. Another particle of

mass M is attached to the rod at one end. The rod is pivoted

at its center. The rod is allowed to rotate from time t =0.

8- The particle begins to move with acceleration(a) 4 g/7 (b)zero (c) g (d) 3 g /79 - Just after time t=0, the force which rod applies on the particle, is(a) M g ( b) 3Mg/7 (c) zero (d) 4Mg /710-When the particle reaches in the lowest position, kinetic energy of the rod alone,will be

(a) M g L /7 (b) zero (c) Mg L /2 (d) 2 M g L /7

11-When the particle reaches in the lowest position , the rod exerts force P upwardon the particle and the pivot support applies Q force upward on the rod and the

angular velocity of the rod is . Which of the following equation/statement is

correct?(a) P + Q -5M g = M 2 L /2 (b) Q -5M g = M 2 L /2

(c) P = M 2 L /2 (d) P + Q = 5M g


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P12-15 : Paragraph for the Q.Nos : 12 to 15A hallow disc of mass M and has outer radius R and inner radius R/3. The disc isplaced on a horizontal ground. A horizontal force F0 is applied

at height h form the ground level. As result the center

of disc which is also center of mass of the disc,

started to move acceleration F0/M and the hallow disc

moves with perfect rolling.

12-The friction force experienced by the hallow disc is(a) zero (b) non zero but lesser than F0

(c) non zero but greater than F0 (d) F0 /3

13-The value of h /R equals(a) 2/3 (b) 4/3 (c) 6/5 (d) 5 /314-During rolling motion , the ratio of the rotational kinetic energy to that oftranslational kinetic energy of disc will be

(a) 2/3 (b) 4/3 (c) 5/3 (d) none

15-If the height of the point of application of the force F0 is increased slightly, andthe ground is enough rough to provide perfect rolling, then the hallow disc will now

roll with acceleration of its center

(a) F0 (b) > F0 (c) < F0 (d) F0 /3

STRAIGHT OBJECTIVE TYPE

16 -A convex lens of focal length 36 cm forms a real image at distance 18 cmfrom its second focal point. If the object is now moved towards the lens by 4mm,the separation between the object and the image will

(a) decrease by nearly 1 mm (b) decrease by nearly 3 mm

(c) decrease by nearly 5 mm (d) increase by nearly 5 mm

17-A small object when placed at distance 50 cm from a person, subtends angleof 10 on the eye of the person. Now a convex lens of focal length 50/4 cm, is

placed at some distance from the object so that the image formed by the lens is

virtual and situated at distance 50 cm from the lens. The angle subtended by the

object on the lens is nearly

(a) 40 (b) 80 (c) 20 (d) 5018- There is a hallow transparent sphere of mean radius R and thickness x


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sphere is cut and is used as lens. This will behave as(a) converging lens of focal length of magnitude nearly R2 / ( 2 x)

(b) diverging of focal length of magnitude nearly R2 / (3 x)

(c) converging lens of focal length of magnitude nearly 2R2 / x

(d) diverging lens of focal length of magnitude 2R2 / x

19- There are two concentric circular coils A and B. The radius of coil A is R andradius of coil B is r. The distance between the centers of the coils is x = R3 and

x>>r . The mutual inductance between the two coils would be approximately

(a) 0 r2 / (16R) (b) 0 r2 / ( 4R) (c) 0 r2 / ( 8R) (d) 0 r2 / (3R)

20-A charge q of mass m, is rotating on a circular path with angular speed .The ratio of the magnetic moment associated with the charge to that of its angular

momentum is

(a) proportional to (b) proportional to m(c) independent of q (d) independent of21-A projectile is projected at certain angle with certain velocity at time t=0. Aboutthe point of projection, its angular momentum at time t is L(t). Then d L(t)/dt is(a) zero always (b) proportional to t

(c) proportional to t2 (d) constant but not zero

22-The net force on a rigid body is zero but torque about center of mass is notzero. Then Which of the following quantities will not change with time?

(a) total kinetic energy (b) angular momentum about CM

(c) rotational kinetic energy (d) translational kinetic energy

23-A conservative force acting in x- direction is changing with x- coordinate asfollowing: F = ( x- 4) ( 2-x).

(a) The particle will be in stable equilibrium at x =2

(b) The particle will be in stable equilibrium at x =4

(c) The particle will be in stable equilibrium at x =3

(d) The particle will be in stable equilibrium both at x =2 and x =4

24-Two identical uniformly dense rods, each of mass m and length L are joined toform a cross. Let there be line in plane of the cross and

the line makes angle from one of the cross.

The moment of inertia about this line will be

(a) m L2cos2 /3 (b) m L2sin2 /12

(c) m L2cos2 /12 (d) m L2 /12

Sample test forJEE -advance op-mag-mech-2 @viresh

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