Recent questions tagged class11

The motion of the sea waves when wind is blowing uniformly can be considered as:

asked Dec 9, 2013 by meena.p

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The mean position and one extreme position of the two different waves represented by $x=23 \sin(2t)$ and $x=5+23 \sin(2t)$ respectively are:

asked Dec 9, 2013 by meena.p

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A stationary observer from far off distance observes a child on the merry go round going round and round in a circle through his binoculars. He sees this motion as:

asked Dec 9, 2013 by meena.p

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The bouncing of a ping pong ball is

asked Dec 9, 2013 by meena.p

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Which are the species in which sulphur undergoes $sp^3$ hybridisation ?

asked Dec 9, 2013 by sreemathi.v

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$ XeF_3^+$ belongs to which one of the following $AX_nE_m$ nomenclatures (A central atom, X singly bonded ligand and E an unshared electron pair) ?

asked Dec 9, 2013 by sreemathi.v

1 answer

The more reactivity of Phosphorouspentachloride $(PCl_5)$ is due to

asked Dec 9, 2013 by sreemathi.v

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Which of the pair is linear in shape and with three lone pairs?

asked Dec 9, 2013 by sreemathi.v

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Where is an electron added during change of $NO^+$ to $NO$

asked Dec 9, 2013 by sreemathi.v

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A hollow sphere of radius R rests on a surface of finite coefficient of friction, A point object of mass m moved horizontally and his the sphere at a height of $\large\frac{R}{2}$ above its centre. The collision is completely inelastic. Which of the following is/are correct ? 1) total linear momentum of the system is not conserved 2) total angular momentum about centre of mass of the system remains constant. 3) the sphere gets finite angular velocity immediately after collision. 4) the sphere moves with finite speed immediately after collision.

asked Dec 9, 2013 by meena.p

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Match the correct formula and shape of the central atom. Which pair is correct?

asked Dec 9, 2013 by sreemathi.v

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The xenon compounds that are isostructural with $IBr_2-$ and $BrO_3-$ respectively are

asked Dec 9, 2013 by sreemathi.v

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The structure of $N(CH_3)_3$ and $N(SiH_3)_3$ are respectively

asked Dec 9, 2013 by sreemathi.v

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The paramagnetism of $O_2$ molecule is believed to be due to the presence of two electrons with parallel spin in

asked Dec 9, 2013 by sreemathi.v

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Which of the following statement is false?

asked Dec 9, 2013 by sreemathi.v

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The structure of $IF_7$ is

asked Dec 9, 2013 by sreemathi.v

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The percentage of p -character in the orbital forming P-P bond in $P_4$ is

asked Dec 9, 2013 by sreemathi.v

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The structure of $XeO_3$ is

asked Dec 9, 2013 by sreemathi.v

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Stable compounds in +1 oxidation state are formed by

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Which element has highest electronegativity ?

asked Dec 9, 2013 by sreemathi.v

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Octahedral molecular shape exist in

asked Dec 9, 2013 by sreemathi.v

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Which of the following molecule is expected to exhibit the diamagnetic behavior?

asked Dec 9, 2013 by sreemathi.v

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Among the following the maximum covalent character is shown by the compound

asked Dec 9, 2013 by sreemathi.v

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The correct sequence which shows the increasing basic strength is

asked Dec 9, 2013 by sreemathi.v

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Using MO theory predict which of the following species has the shortest bond length

asked Dec 9, 2013 by sreemathi.v

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Match the each of the diatomic molecule in column-I with the bond orders are given in the column -II

asked Dec 9, 2013 by sreemathi.v

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The torque $\overrightarrow{z}$ on a body about a given point is found to be $ \overrightarrow{A} \times \overrightarrow{L}$ where $\overrightarrow {A}$ is a constant vector and $\overrightarrow{L}$ is angular momentum about that point . From this it follows that. 1) $\large\frac{dL}{dt}$ is perpendicular to $\overrightarrow {L}$ at all times 2) the component of $\overrightarrow {L}$ in the direction of $\overrightarrow{A}$ does not change with time. 3) the magnitude of $\overrightarrow {L}$ does not change with time. 4) $\overrightarrow {L}$ does not change with time. Which of the following is correct?

asked Dec 9, 2013 by meena.p

1 answer

A ring without slipping on a horizontal surface. At any instant , its position is as shown in figure. 1) Section ABC has greater kinetic energy than ADC 2) Secion BC has same kinetic energy as section DA 3) Secion BC has greater kinetic energy than section DA 4) the Secion AB,BC,CD and DA have same kinetic energy Which of the following is correct?

asked Dec 9, 2013 by meena.p

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A ring rolls without slipping on the ground. Its centre C moves with a constant speed u. P is any point on the ring. The speed of P with respect to the ground is V. 1) $0 \leq v \leq 2u$ 2) $v=u $, if CP horizontal 3) $v=u$ if CP makes an angle of $60^{\circ}$ with the horizontal and p is below the horizontal level of C 4) $v= \sqrt 2 u$ if CP is horizontal Which of the following is correct?

asked Dec 9, 2013 by meena.p

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A thin uniform rod of mass m and length l is rotate about its upper end. When it is at rest, it receives an impulse J at its lowest point normal to its length. Immediately after impact, 1) the angular mometum of the rod is $JL$ 2) the angular velocity of the rod is $\large\frac{3J}{ml}$ 3) the kinetic energy of the rod is $\large\frac{3J^2}{2m}$ 4) the linear velocity of the midpoint of the rod is $\large\frac{3J}{3m}$ Which of the following is correct?

asked Dec 9, 2013 by meena.p

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The motion of a sphere moving on a rough horizontal surface change from pure sliding (without rolling) to pure rolling (with out slipping) . In this process, the force of friction. 1) initially acts opposite to the direction of motion and later in the direction of motion. 2) causes linear retardation 3) causes angular acceleration 4) stops acting when pure rolling begins. Which of the following is correct?

asked Dec 9, 2013 by meena.p

1 answer

Two identical spheres A and B are free to move and to rotate about their centres. They are given the same impacts J. The line of action of the impulses pass through the centre of A and away from the centre of B.

asked Dec 9, 2013 by meena.p

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A constant external torque acts for a very brief $\Delta t$ on a rotating system having moment of inertia I.

asked Dec 8, 2013 by meena.p

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Two horizontal discs of different radius are free to rotate about their central vertical axes. One is given some angular velocity, the other is stationary . Their rims are now brought in contact. There is friction between the rims.

asked Dec 8, 2013 by meena.p

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A horizontal disc rotates freely about a vertical axis through its centre. A ring, having the same mass and radius as the disc , is now gently placed on the disc. After some time, the two rotate with a common angular velocity. 1) some friction exits between the disc and the ring 2) the angular mometum of disc plus ring is conserved. 3) the final common angular velocity is $\large\frac{2}{3}$ rd of the initial angular velocity of disc. 4) $\large\frac{2}{3}$ rd of the initial kinetic energy is converted to heat. Which of the following is correct?

asked Dec 8, 2013 by meena.p

1 answer

A man standing on a platform holds weight in his out stretched arms. The system rotates freely about a central vertical axis. If he now draws the weights inwards close to his body. 1) the angular velocity of the system will decrease 2) the angular momentum of the system will decrease. 3) the kinetic energy of the system will increase 4) he will have to expend some energy to draw the weights in Which of the following is correct?

asked Dec 8, 2013 by meena.p

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A man spinning in free space changes of his body e.g by spreading his arms and curling up. By doing this, he can change his 1) moment of inertia 2) angular momentum 3) angular velocity 4) rotational kinetic energy in this Which of the following is correct?

asked Dec 8, 2013 by meena.p

2 answers

A body is in equilibrium under the influence of a number of a forces. Each force has a different line of action. The minimum number of forces required is

asked Dec 8, 2013 by meena.p

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When slightly different weights are placed on the two pane of a beam balance, the beam comes to rest at an angle with the horizontal. The beam is supported at a single point P by a pivot.

asked Dec 8, 2013 by meena.p

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A particle of mass m is travelling with a constant velocity $\overrightarrow {V} =V_0 \hat i$ along the line $y=b,z=0$. Let $dA$ be the area swept out by the position vector from the origin to the particle in time at end L be the magnitude of angular momentum of particle about orgin at any time t. Then 1) L= constant 2) $\large\frac{dA}{dt}=\frac{L}{m}$ 3) $\large\frac{dA}{dt}= \frac{2L}{m}$ 4) $\large\frac{dA}{dt}=\frac{L}{2m}$ Which of the following is correct?

asked Dec 8, 2013 by meena.p

1 answer

A spherical body of radius R rolls on a horizontal surface with linear velocity $V$. Let $L_1$ and $L_2$ be the magnitude of angular momentum of the body about the centre of mass and point of contact P respectively. a) $L_2=L_1$ if radius of gyration $k=R$ b) $L_2=2L_1$ for all cases. c) $L_2 > 2L_1$ if radius of gyration $K < R$ d) $L_1> L_2$ if radius of gyration $ K > R$ Which of the following is correct?

asked Dec 8, 2013 by meena.p

1 answer

A disc can roll without slipping without applying any external force on a 1) rough inclind plane 2) smooth inclined plane 3) rough horizontal surface 4) smooth horizontal surface Which of the following is correct?

asked Dec 8, 2013 by meena.p

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Which of the following statements are correct for a spherical body rolling without slipping on a rough horizontal ground at rest.

asked Dec 6, 2013 by meena.p

1 answer

A cubical block of side a is moving with a velocity v on a smooth horizontal plane as shown. It hits a ridge at point O. The angular speed of the block when it hits O is

asked Dec 6, 2013 by meena.p

1 answer

For toppling of the regular hexagon shown. the coefficient of friction must be

asked Dec 6, 2013 by meena.p

1 answer

The bond energy (in kcal/mol) of C-C single bond is approximately

asked Dec 6, 2013 by sreemathi.v

1 answer

A block with a square base measuring $a \times a$ and height h, is placed on an inclined plane. The coefficient of friction is $\mu$. The angle of inclination $(\theta)$ of the plane is gradually increased. The block will

asked Dec 6, 2013 by meena.p

1 answer

Which of the following species has bond order different from that in CO?

asked Dec 6, 2013 by sreemathi.v

1 answer

A uniform cube of side 'a' and mass 'm' rests on a rough horizontal table. A horizontal force 'F' is applied normal to one of the faces at a point that is directly above at a height $\large\frac{3a}{4}$ above the base. The minimum value of 'F' for which the cube begins to lilt about the edge is (assume cube does not slide)

asked Dec 6, 2013 by meena.p

1 answer

Which of the following is a false statement?

asked Dec 6, 2013 by sreemathi.v

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